Coloboma of macula–brachydactyly type B syndrome is a very rare genetic condition that affects both the eyes and the hands/feet from birth and lasts for life. In this syndrome, the very center of the retina (the macula) has a “hole-like” defect called a macular coloboma, and the fingers and toes have missing or very short end bones, which is called brachydactyly type B. Children usually have poor central vision, involuntary eye movements (nystagmus), and short or absent tips of several fingers and toes, often with missing nails. The condition is inherited in an autosomal dominant way, which means one changed copy of the gene from an affected parent is enough to cause the syndrome. Only a small number of related people in one British family have been clearly described, so it is considered an ultra-rare disorder.
Coloboma of macula-brachydactyly type B syndrome (also called Sorsby syndrome) is a very rare genetic condition. It affects the macula (the central part of the retina that gives sharp vision) and the fingers and toes. People are born with a central eye defect called macular coloboma and with short or missing end bones of the fingers and toes (brachydactyly type B). Symptoms are present from birth and last for life.[1][2]
Scientists think that the eye problem (macular coloboma) comes from a disturbance in early eye development, when the back of the eye is forming, and that the hand and foot problems are linked to changes in genes that guide the growth of the last bones of the digits. The combination of these two features in the same person makes this syndrome different from simple coloboma or simple brachydactyly alone.
Other names
This syndrome has several other names used in medical books and rare-disease databases. All these names refer to the same underlying condition.
Other names
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Sorsby syndrome
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Coloboma of macula with type B brachydactyly
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Coloboma of macula–brachydactyly type B syndrome
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Macular coloboma with brachydactyly type B
Even though there is only one officially described family, doctors sometimes talk about “types” or patterns of the condition based on how severe the eye and limb problems are. These are not formal medical subtypes, but they are a simple way to think about the range of features that have been seen in people with macular coloboma and brachydactyly type B.
Types
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Mild form – The person has clear macular coloboma on eye exam and visible changes in the fingers and toes, but vision may be partly usable, and hand function may still be fairly good. They might read with large print and manage daily tasks with some adjustments.
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Classic form – This is the pattern most often described. There is bilateral (both eyes) macular coloboma with marked loss of central vision, horizontal pendular nystagmus, and typical brachydactyly type B with short or missing end bones and nails in several digits, often with broad or split thumbs and big toes and webbing between digits.
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Severe form – In some descriptions of Sorsby-like families, the skeletal changes are more widespread, with short limbs, marked shortening or absence of many phalanges, and other findings such as hearing loss or dental abnormalities, along with severe visual loss. Not every person with this gene change will have all of these features, which shows that the same gene change can act differently in different people.
Because the condition is so rare, doctors treat every affected family carefully and may use terms like “mild,” “classic,” or “severe” only to describe what they see, not as fixed labels.
There is only one main genetic syndrome, but doctors often group the features into “types of problems” to make it easier to understand what is happening in the body.
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Eye-related problems – bilateral macular coloboma, horizontal pendular nystagmus, and severe central visual loss. These are the core eye findings and usually appear very early in life.
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Hand and finger problems – shortening or absence of the middle and end bones of fingers 2–5, with very small or absent nails and sometimes broad or split thumbs. This pattern matches brachydactyly type B.
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Foot and toe problems – similar shortening of some toe tips and nails, usually less severe than in the hands, but still clearly visible on examination and X-ray.
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Joint and soft tissue problems – flexion contractures (bent fingers), camptodactyly, and syndactyly, which can limit finger straightening and make hand movements stiff or awkward.
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Other body problems (sometimes present) – some reports mention kidney agenesis (missing kidney) and short stature in affected people, so doctors may also check the kidneys and growth.
These groups do not represent separate official subtypes but simply different clusters of features that doctors pay attention to when describing and managing the same rare syndrome.
Causes and risk factors
1. Mutation in a brachydactyly-related gene (such as ROR2)
Brachydactyly type B is known to be caused by harmful changes (mutations) in genes such as ROR2, which encodes a receptor involved in bone development. In families with brachydactyly type B, truncating or other damaging mutations in ROR2 disturb the formation of the last bones and nails in the digits. In Sorsby-type families, a similar mechanism is believed to explain the hand and foot changes that occur together with macular coloboma.
2. Autosomal dominant inheritance
The syndrome is inherited in an autosomal dominant pattern. This means that if one parent carries the disease-causing mutation, there is a 50% chance in each pregnancy that the baby will inherit the mutation and the condition. In the original reported family, the syndrome affected several members across four generations, which supports this autosomal dominant pattern.
3. De novo (new) mutation in the egg or sperm
In some families with similar brachydactyly type B or macular coloboma, the mutation can arise for the first time in the sperm or egg that formed the child, even if both parents have normal hands and feet and normal vision. This is called a de novo mutation. In such cases, the affected child can later pass the mutation to his or her own children.
4. Abnormal closure of the optic fissure in early eye development
Coloboma in general is thought to result from incomplete closure of a groove in the developing eye called the optic fissure, which normally closes between the 5th and 7th week of pregnancy. If this groove does not close properly in the region that forms the macula, a macular coloboma can form. This developmental interruption is considered a core cause of the eye part of this syndrome.
5. Disturbed development of the macula
The macula is the central area of the retina that gives sharp, detailed vision. In macular coloboma, the tissue in this area is thin, absent, or replaced by a scar-like defect. Studies suggest that errors in the retinal layers’ differentiation and in the support tissues underneath can lead to this defect. In Sorsby syndrome, this disturbed macular development happens along with the hand and foot bone changes.
6. Disturbed growth of distal phalanges
In brachydactyly type B, the terminal and sometimes middle phalanges of fingers and toes are missing or shortened. This is due to disturbed signaling in the growth plates and patterning centers that tell the limb bud where and how long the bones should grow. When these signals are abnormal because of gene mutations, the tips of the digits may not form at all.
7. Disturbed nail development (anonychia)
The same developmental error that damages the last phalanx also affects the tissue that gives rise to the nail unit. As a result, nails can be absent (anonychia) or very underdeveloped in several digits. This characteristic feature is commonly noted in brachydactyly type B and in the described Sorsby family.
8. Variable expressivity of the same mutation
Even within one family, the same mutation can cause slightly different levels of severity in different people, a phenomenon called variable expressivity. Some relatives may have more severe eye changes, while others show more severe digit shortening or extra skeletal features. This means that the “cause” is the same mutation, but its visible effects differ from person to person.
9. Possible involvement of other modifier genes
Research on brachydactyly and syndromic coloboma suggests that more than one gene can influence how the features look. Modifier genes may make the macular lesion larger or smaller, or change how much the digits are shortened. While specific modifier genes have not been proven for this exact syndrome, the general concept is supported by genetic studies in related conditions.
10. NOG and other brachydactyly-related genes
Some people with brachydactyly type B who do not have ROR2 mutations have changes in another gene called NOG, which encodes the protein noggin and helps regulate bone formation. In theory, similar mutations could contribute to combined eye–limb conditions, although for this exact syndrome, ROR2-type mechanisms are better documented.
11. General genetic heterogeneity of ocular coloboma
Coloboma is a genetically heterogeneous condition. Many genes involved in eye patterning, cell adhesion, and signaling have been linked with ocular coloboma in general. This background of genetic complexity suggests that different gene combinations might influence whether a person develops isolated macular coloboma or a syndrome that also includes limb changes.
12. Possible intrauterine infection affecting eye development
In case reports of macular coloboma, authors have discussed the possibility that certain infections in pregnancy (for example, infections in the TORCH group) could interfere with development of the macula and leave a coloboma-like defect. For Sorsby syndrome, the main cause is genetic, but infections are considered in the differential diagnosis when doctors first see a baby with similar retinal lesions.
13. Environmental exposures in pregnancy (probable but not proven)
Animal and human data suggest that some drugs, toxins, or vitamin imbalances during pregnancy can disturb eye and limb formation. For example, abnormal vitamin A signaling is a known risk factor for some eye malformations. For this specific syndrome, no single environmental exposure has been proven, but clinicians still ask about maternal exposures because they may explain some coloboma-like cases without a clear gene mutation.
14. Copy-number or chromosomal changes involving eye–limb genes
In syndromic ocular coloboma, some patients have chromosomal deletions or duplications that include important developmental genes. In theory, a structural change involving a region that carries a brachydactyly gene plus eye-development genes could produce a similar combined picture. Such events are rare but part of the broader group of genetic causes that doctors consider.
15. Parental germline mosaicism
Sometimes a mutation is present only in some of a parent’s egg or sperm cells but not in their blood or body cells. This is called germline mosaicism. In such cases, more than one child can be affected, even though standard testing of the parents appears normal. Germline mosaicism has been described in other dominant skeletal disorders and is a plausible mechanism in rare familial macular coloboma–brachydactyly combinations.
16. Consanguinity increasing the chance of rare variants
In communities where parents are closely related, there is a higher chance that both carry the same rare variant. Although Sorsby syndrome is dominantly inherited, consanguinity can still influence how rare gene variants are shared within a family, which can complicate the genetic picture and increase the clustering of unusual disorders.
17. Epigenetic changes in early embryo
Epigenetic changes are chemical marks on DNA that affect how genes are switched on or off without changing the DNA letters themselves. Environmental factors or random events early in development can alter these marks. Researchers studying eye and limb development believe epigenetic dysregulation may help explain why even people with the same mutation can have different severity, although this has not yet been proven specifically for this syndrome.
18. Random developmental variation
Embryonic development is a complex process, and sometimes, even with the same genetic information, small random differences in cell behavior can lead to different outcomes. This developmental “noise” may partly explain why the macular coloboma size or the exact pattern of finger shortening varies among affected family members.
19. Coexisting skeletal features beyond the hands and feet
Some people with Sorsby-like syndromes have broader skeletal features such as short limbs and spinal changes. These likely reflect the same genetic disturbance acting more widely in the skeleton. In this way, the bone component of the syndrome can be seen as a spectrum, from digits only to more widespread skeletal involvement, all arising from the same primary genetic cause.
20. Lack of preventive factors
At present, there is no known way to prevent this syndrome once the mutation is present. This fact itself is sometimes listed as a “cause-related” point: the condition arises from fixed genetic changes rather than modifiable lifestyle factors. Prevention efforts therefore focus on genetic counseling and informed family planning rather than on changing environmental risks.
Symptoms and clinical features
1. Macular coloboma
The main eye feature is a coloboma in the macula, the central part of the retina that normally gives sharp, detailed vision. On eye exam, doctors see a pale, excavated or scar-like area in the macula where retinal tissue is absent or abnormal. This structural defect is present from birth and does not heal over time.
2. Severe central vision loss
Because the macula is damaged, people with this syndrome have poor central vision in both eyes. They may not be able to read normal print, recognize faces from a distance, or see fine details. Peripheral vision may be better preserved, so they may still move around in familiar spaces with training and aids.
3. Horizontal pendular nystagmus
Many affected people show horizontal pendular nystagmus, which means the eyes move back and forth in a smooth, repetitive way from side to side. This happens because the brain tries to find a better position for vision when the central retina is damaged. Nystagmus is usually noticed in early infancy when the baby seems to have “shaky eyes.”
4. Poor visual acuity on eye charts
When older children or adults are tested with standard eye charts, their best-corrected visual acuity is often very low, and glasses can correct only a small part of the problem, because the macular tissue itself is malformed. This distinguishes macular coloboma from simple refractive errors like short-sightedness.
5. Difficulties with reading and near tasks
Because of the central vision loss, reading printed text, using computers, and doing schoolwork that needs close detail can be very hard. Many patients need large-print materials, magnifiers, or electronic low-vision devices to read. Occupational therapy can help them learn alternative strategies.
6. Light sensitivity and visual discomfort
Some people with macular coloboma report glare and discomfort in bright light. The abnormal retinal surface can scatter light differently, and nystagmus can make bright light more bothersome. Tinted lenses and hats are often suggested to make outdoor activities more comfortable.
7. Short or missing end bones of fingers
The hallmark hand feature is short or completely missing terminal phalanges (end bones) of the second to fifth fingers, and sometimes parts of the middle phalanges as well. The fingertips may look blunt or absent, and the digits end suddenly. This pattern matches brachydactyly type B and is a key clue to the diagnosis when seen with macular coloboma.
8. Short or missing end bones of toes
Similar changes occur in the toes, especially the second to fifth toes. The tips may be very short, absent, or fused. These features can make shoe fitting difficult and may affect balance and walking, although many people adapt well, especially with proper footwear.
9. Absent or underdeveloped nails (anonychia or nail dysplasia)
Many digits have missing or very small, thin nails. This is called anonychia (no nails) or nail dysplasia (poorly formed nails). It happens because the nail-forming tissue did not develop properly on top of the malformed bone. While this does not usually cause pain, it is cosmetically noticeable and part of the diagnostic picture.
10. Broad or split thumbs and big toes
The thumbs and big toes (halluces) can be broad or split at the tip (bifid), giving them a forked or doubled appearance. This is often described in Sorsby syndrome and in brachydactyly type B more generally. These changes reflect abnormal patterning signals in the developing limb bud.
11. Webbing between fingers or toes (syndactyly)
Syndactyly, or fusion of soft tissue between digits, is common. The skin between two or more fingers or toes may not separate fully before birth, leaving webbing. This can limit the spread of the digits and affect grasp or balance, though surgery can sometimes improve function.
12. Bent or stiff finger joints (camptodactyly and flexion deformities)
Some joints in the fingers and toes may be permanently bent (flexion contractures), a feature called camptodactyly. The joints may not fully straighten, which can further limit hand function and fine motor skills. Stretching, splinting, or surgery may be considered depending on severity.
13. Difficulty with fine motor tasks
Because of the shortened digits, missing nails, and bent joints, many everyday tasks that require precise finger movements become challenging. Examples include buttoning clothes, writing, tying shoelaces, and manipulating small objects. Occupational therapists can teach adapted techniques and recommend assistive devices.
14. Possible short stature or limb disproportion in some families
In some reported Sorsby-like families, affected individuals show short-limbed dwarfism and more generalized skeletal changes in addition to hand and foot anomalies. Not every person with macular coloboma–brachydactyly type B has short stature, but it is an important feature to look for when assessing family members.
15. Psychosocial and emotional impact
Living with both severe visual impairment and visible differences in the hands and feet can be emotionally difficult. Children may face bullying or social exclusion, and adults may worry about work, independence, and relationships. Support from family, low-vision services, psychological counseling, and peer groups can greatly improve quality of life.
Diagnostic tests
Physical examination
1. General pediatric and dysmorphology exam
A detailed physical exam by a pediatrician or clinical geneticist looks at height, body proportions, facial features, and the pattern of limb changes. The doctor checks for short stature, limb disproportion, and other skeletal signs that may go along with the hand and foot findings. This exam helps decide whether the person has a limited hand–foot condition or a wider skeletal syndrome.
2. External eye exam and slit-lamp inspection
An ophthalmologist examines the eyes with a light and special microscope (slit lamp) to look at the front of the eye and to check for other problems such as small eyes (microphthalmia), cataracts, or lens issues that sometimes appear in coloboma syndromes. This step ensures that no treatable front-of-eye problems are missed.
3. Dilated fundus examination
The pupils are widened with eye drops, and the retina is examined with lenses and ophthalmoscopes. In this syndrome, the doctor sees a bilateral macular coloboma—pale, excavated lesions at the center of each retina. The rest of the retina is checked for other colobomas, scars, or signs of inflammation, which helps distinguish this syndrome from other causes of macular scars.
4. Detailed hand and foot examination
The hands and feet are inspected for digit length, shape, nail presence, webbing, and joint position. The pattern of missing terminal phalanges, anonychia, broad or split thumbs and halluces, and syndactyly is typical for brachydactyly type B and supports the diagnosis when seen together with macular coloboma.
Manual and bedside tests
5. Visual acuity testing with eye charts
Age-appropriate eye charts or picture charts are used to measure how well the person can see at a distance and near. Even with the best glasses, people with macular coloboma usually have reduced acuity because the macula itself is malformed. This test quantifies the level of visual disability and guides low-vision support.
6. Refraction test with trial lenses
The eye doctor places different lenses in front of the eyes or uses a machine to find out whether the person is short-sighted, long-sighted, or has astigmatism. Correcting these refractive errors can improve the remaining vision, even if the macular damage cannot be fixed, so this test is still important for maximizing function.
7. Amsler grid and central field checks
An Amsler grid is a simple square grid that the patient looks at while covering one eye at a time. People with macular coloboma often see a blank patch, distortion, or missing lines in the center of the grid. This quick manual test helps demonstrate central field loss and can be used to monitor stability over time.
8. Basic hand function and grip strength tests
Doctors or therapists ask the person to pick up small objects, button clothing, and use simple tools, and they may measure grip strength with a handheld device. These tests give a practical sense of how much the brachydactyly and joint deformities affect daily living, and they help plan occupational therapy and possible hand surgery.
Lab and pathological tests
9. Targeted gene testing for ROR2
Because ROR2 mutations are a well-known cause of brachydactyly type B, molecular testing of this gene is a key diagnostic step. A blood sample is taken, DNA is extracted, and the gene is sequenced to look for harmful variants. Finding a likely pathogenic ROR2 mutation in a person with macular coloboma and brachydactyly strongly supports the diagnosis and allows testing of relatives.
10. Gene panel or exome sequencing including NOG and coloboma genes
If ROR2 testing is negative or if the clinical picture is atypical, broader next-generation sequencing panels or exome sequencing can be used. These tests look at many genes at once, including NOG and other genes linked to brachydactyly, as well as genes known to cause ocular coloboma. This approach improves the chance of finding a molecular diagnosis in rare or complex cases.
11. Chromosomal microarray or structural variant analysis
Chromosomal microarray looks for deletions or duplications of larger segments of DNA across the genome. In some syndromic coloboma conditions, such copy-number changes have been found. While this is not the classic mechanism for Sorsby syndrome, microarray may be used when the phenotype is broader or when initial gene testing is negative, to rule out larger genomic changes.
12. Infection screening to rule out other macular scars
Blood tests for congenital infections (such as toxoplasmosis and other TORCH infections) may be done in infants with macular lesions that look like colobomas. If infection tests are negative and the retinal appearance is consistent with a true coloboma, the diagnosis of a developmental defect becomes more likely, supporting a syndrome such as macular coloboma–brachydactyly type B.
13. Basic metabolic and systemic screening
Routine blood tests and screening for other systemic disorders may be ordered to exclude more common syndromes that can involve limb anomalies and eye findings. When these tests are normal and the specific pattern of macular coloboma plus brachydactyly type B is present, the rare Sorsby syndrome diagnosis is considered more strongly.
Electrodiagnostic tests
14. Electroretinography (ERG)
ERG measures the electrical response of the retina to light flashes. In macular coloboma, ERG may show relatively preserved peripheral retinal function but abnormal signals from the central retina. This helps confirm that the main problem is a structural defect in the macula, not a generalized retinal degeneration.
15. Visual evoked potentials (VEP)
VEP tests record electrical activity in the visual cortex of the brain when the eyes see patterned stimuli. In severe central vision loss, VEP responses can be reduced or delayed. VEP is especially useful in babies or non-verbal patients to objectively assess whether visual pathways are working at all, beyond what can be seen on imaging.
16. Nerve conduction studies and EMG (if needed)
Although this syndrome mainly affects bones and eyes, doctors sometimes perform nerve conduction studies and electromyography (EMG) if there are symptoms such as weakness, numbness, or suspicion of another neuromuscular condition. Normal results support the idea that the limb problem is due to bone and joint malformation, not nerve or muscle disease.
Imaging tests
17. Optical coherence tomography (OCT) of the macula
OCT is a non-invasive imaging test that uses light waves to take cross-section pictures of the retina. In macular coloboma, OCT shows loss or thinning of the retinal layers and sometimes a depression or cavity in the macular region. OCT helps distinguish true coloboma from other macular diseases that may look similar but have different patterns on cross-section.
18. Fundus photography or wide-field retinal imaging
Color photographs of the retina provide a permanent record of the macular coloboma and any other retinal features. Wide-field imaging can show whether there are additional peripheral colobomas or other lesions. Serial photographs over time help monitor stability and document changes for teaching and research.
19. Fluorescein angiography (FA) when needed
In FA, a fluorescent dye is injected into a vein, and pictures of the retina are taken as the dye passes through the retinal blood vessels. In macular coloboma, FA can show areas where the choroid and retinal pigment epithelium are absent, confirming the depth and extent of the defect. FA also helps rule out conditions such as inflammatory scars or vascular diseases that might mimic the appearance of coloboma.
20. X-rays of hands and feet
Radiographs (X-rays) of the hands and feet are crucial to confirm brachydactyly type B. They show the exact bones that are missing or shortened, the shape of the remaining phalanges, and any fusions between bones. This radiographic pattern is highly characteristic and, when combined with macular coloboma, points strongly to coloboma of macula–brachydactyly type B syndrome.
Non-pharmacological treatments (therapies and others)
1. Low-vision rehabilitation
Low-vision clinics teach the child or adult how to use remaining vision better. They use magnifiers, high-contrast reading materials, large-print books, and lighting advice. Training helps people find faces, read, and move safely even with poor central vision.[4][6]
2. Optical aids and electronic devices
Magnifying glasses, telescopic lenses, high-power spectacles, and electronic video magnifiers (CCTV or tablet apps) can enlarge text and objects. This reduces eye strain and helps with school and daily tasks like reading medicine labels or money.[4]
3. Orientation and mobility training
Specialists teach safe walking, use of contrasting edges, and sometimes training with a cane in very low vision. This reduces falls and builds confidence in unfamiliar places like new schools or streets.[5][6]
4. Educational support and special accommodations
Schools can give extra time for reading, seat the child near the board, use large-print materials, or allow audio books. Early support prevents learning delays that are due only to visual problems, not intelligence.[2][4]
5. Occupational therapy for hand function
Occupational therapists help children practice fine-motor tasks with adapted tools (modified pens, cutlery, buttons). They suggest grips, splints, and home exercises to make daily tasks easier despite short or missing finger segments.[3]
6. Physiotherapy and stretching programs
Physiotherapists design exercises to keep joints flexible and prevent worsening of camptodactyly or stiffness. Regular stretching can maintain the best possible range of movement in fingers, wrists, and ankles.
7. Custom splints and orthoses
Splints can hold joints in more functional positions, especially in flexed fingers or toes. For feet, orthotic inserts and special shoes can improve balance and reduce pain during walking.
8. Environmental and home modifications
Good lighting, high-contrast markings on stairs, anti-slip mats, and clutter-free floors make the home safer. Large-print labels on medications and food packages support independent living.
9. Psychological counselling and family support
Because this syndrome changes appearance and vision, children and parents may feel stressed or sad. Counselling helps families manage anxiety, bullying, and body-image issues, and supports healthy self-esteem.[2]
10. Genetic counselling
Genetic counsellors explain inheritance, recurrence risk in future pregnancies, and options such as prenatal or pre-implantation genetic diagnosis where available. This helps families make informed reproductive decisions.[1][3]
11. Early-intervention developmental programs
For babies and toddlers, early-intervention services provide visual stimulation, motor exercises, and parenting guidance. Starting early helps the child reach developmental milestones as fully as possible.
12. Vocational rehabilitation (for adults)
Adults can receive training to choose jobs compatible with vision and hand function, learn adaptive computer technologies, and plan safe working environments.
13. Social support groups and peer networks
Meeting other families with rare visual or limb conditions reduces isolation and allows sharing of coping strategies and practical tips. Online and in-person groups can be very helpful.
14. Fall-prevention and safety training
Teaching safe navigation, avoiding loose rugs, and using handrails lowers the risk of falls, especially when central vision is poor or depth perception is affected.
15. Hand-skills training for specific tasks
Focused practice on writing, keyboard use, eating, dressing, or playing musical instruments can help the brain and remaining finger segments adapt and work more efficiently.
16. Assistive technology for communication and learning
Screen readers, speech-to-text, and high-contrast interfaces on computers and smartphones allow better access to reading, messaging, and online education.
17. Pain-management physiotherapy
If joint or post-surgical pain occurs, non-drug methods like heat packs, cold packs, gentle massage, and relaxation training can reduce discomfort and dependence on pain medicines.
18. Sun-protection strategies
Sunglasses with UV protection, hats with brims, and avoiding bright midday sun help reduce glare and protect fragile retinal tissue.
19. Regular ophthalmology and orthopaedic follow-up
Scheduled visits allow early detection of retinal tears, detachment, cataract, or joint problems, so that treatment can start before serious damage occurs.[4][6]
20. Family education and written care plans
Clear written plans explain warning signs (flashes, floaters, sudden loss of vision, new hand pain), emergency steps, and routine care. This empowers families to act quickly if problems arise.
Drug treatments
Important:
There are no medicines that directly cure Coloboma of macula-brachydactyly type B syndrome. The drugs below are FDA-approved for related problems (like eye inflammation, infection, retinal disease, or pain) and may be used by specialists when needed. Doses and timing must always be set by a doctor, especially in children. Information is based on FDA-approved prescribing data and ophthalmology practice guidelines.[7][8][9][10]
I will briefly give drug class, typical adult dose example, timing, purpose, main mechanism, and key side-effects in simple language.
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Carboxymethylcellulose artificial tears
Class: Lubricant eye drops.
Dose/time: 1–2 drops in affected eye(s) up to 4–6 times daily.
Purpose: Relieves dryness, irritation, and surface discomfort.
Mechanism: Forms a moist film over the eye, reducing friction.
Side-effects: Temporary blur, mild burning; serious reactions are rare. -
Carbomer or hydroxypropyl-methylcellulose eye gel
Thicker gel for night-time use to keep eyes moist during sleep. May be used once at bedtime. Can cause brief blurring and sticky lids. -
Erythromycin ophthalmic ointment
Class: Topical antibiotic.
Used 2–4 times daily for short courses to prevent or treat surface bacterial infection after minor eye injury or surgery. Works by blocking bacterial protein synthesis. May cause mild redness or irritation. -
Moxifloxacin ophthalmic solution
Class: Fluoroquinolone antibiotic eye drop.
Used every few hours initially for serious corneal infection risk, as advised by an ophthalmologist. Kills bacteria by blocking DNA replication. Can cause temporary burning; rare allergic reactions. -
Prednisolone acetate 1% eye drops
Class: Topical corticosteroid.
Used short-term (for example, 4 times daily then tapered) to reduce inflammation after surgery or with associated uveitis. Blocks inflammatory chemicals. Side-effects: raised eye pressure, delayed healing, cataract risk if overused. -
Cyclopentolate 1% eye drops
Class: Cycloplegic/midriatic.
Used in clinic to dilate the pupil and relax focusing muscle for accurate eye exams or amblyopia treatment. Side-effects: light sensitivity, blur, rarely flushing or behavior changes in children. -
Atropine 1% eye drops
Similar class; sometimes used in amblyopia management to blur the stronger eye so the weaker eye works harder. Can cause strong light sensitivity, near-vision blur, and systemic effects if overused, so dosing must be carefully supervised. -
Ranibizumab intravitreal injection
Class: Anti-VEGF biologic.
Injected into the vitreous of the eye at intervals (for example monthly, then less often) for complications such as macular neovascularization in some retinal diseases. It blocks VEGF, a growth factor that drives abnormal blood vessels.[9] Side-effects: injection-related discomfort, rare infection, retinal detachment. -
Aflibercept intravitreal injection
Another anti-VEGF agent with similar purpose, used for several retinal vascular conditions. It traps VEGF and related factors. Side-effects are similar to ranibizumab. -
Brolucizumab intravitreal injection
A newer anti-VEGF drug with longer duration for some patients. It is injected less frequently but has a known risk of intraocular inflammation and vasculitis, so close monitoring is essential.[9] -
Bevacizumab intravitreal (off-label in many countries)
Originally an anti-VEGF cancer drug, often used off-label in eye care because it is effective and lower cost. Mechanism and side-effects are similar; usage depends on local guidelines. -
Dexamethasone intravitreal implant
Class: Corticosteroid implant.
Used for certain macular edemas to reduce inflammation over months. It slowly releases steroid inside the eye. Risks: raised intraocular pressure and cataract formation, so pressure must be monitored. -
Acetazolamide (oral)
Class: Carbonic anhydrase inhibitor.
Sometimes used short-term to reduce eye fluid and pressure or macular edema in selected patients. It reduces fluid production in the eye. Side-effects: tingling of fingers, frequent urination, kidney stone risk, taste changes. -
Paracetamol (acetaminophen)
Class: Analgesic and antipyretic.
Typical adult oral dose is 500–1000 mg every 4–6 hours (maximum 3–4 g/day), used for post-surgical or musculoskeletal pain. It blocks pain signals in the brain. Overdose can cause serious liver damage. -
Ibuprofen
Class: Non-steroidal anti-inflammatory drug (NSAID).
Adult dose often 200–400 mg orally every 6–8 hours with food for short-term pain. Reduces prostaglandins that cause pain and inflammation. Side-effects: stomach irritation, kidney stress, bleeding risk in some patients. -
Oral amoxicillin–clavulanate
Class: Broad-spectrum antibiotic.
Used after hand or foot surgery if there is infection risk. Works by blocking bacterial cell-wall construction. Side-effects: diarrhea, rash, allergic reactions, especially in penicillin-allergic people. -
Peri-operative cefazolin (IV)
Given just before and sometimes after surgery on hands or eyes to prevent surgical-site infection. Acts on bacterial cell walls. Side-effects: allergic reactions, diarrhea, rare kidney or blood effects. -
Gabapentin
Class: Neuropathic pain modulator.
Sometimes used for persistent nerve-type pain after major surgery or in associated neuropathies. It calms overactive nerve firing. Side-effects: sleepiness, dizziness, weight gain; needs gradual dose changes. -
Lidocaine local anesthetic (drops or injection)
Used by eye and hand surgeons to numb the area for short procedures. It blocks nerve signals in the treated region. Side-effects are rare when doses are controlled, but overdose can affect heart rhythm or cause seizures. -
Ondansetron
Class: Anti-nausea agent.
Used around surgery to reduce vomiting and nausea. It blocks serotonin receptors in the gut and brain. Side-effects: headache, constipation, rare heart-rhythm changes.
Dietary molecular supplements
Note: No vitamin or supplement has been proven to cure this syndrome. These examples support general eye, nerve, and bone health. Always ask a doctor before starting them, especially in children or pregnancy.
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Omega-3 fatty acids (fish oil or algae oil)
Help support retinal and nerve cell membranes and may reduce inflammation. Typical adult dose: 500–1000 mg EPA+DHA daily with food. Main side-effects: fishy after-taste, mild stomach upset, bruising risk at very high doses. -
Lutein and zeaxanthin
Carotenoids that concentrate in the macula and may protect against light-induced damage. Often taken as 10–20 mg lutein plus 2 mg zeaxanthin daily. Side-effects are rare; high doses may cause harmless yellowing of skin. -
Vitamin A (within safe limits)
Important for the visual cycle and retinal function. Usually obtained from diet or multivitamins; high-dose supplements are not advised without specialist supervision, because excess vitamin A can damage liver and bones. -
Vitamin D
Supports bone health and immune function. Many children and adults are deficient. Typical supplemental doses range from 600–2000 IU/day depending on age and blood levels. Excessive doses can cause high calcium and kidney problems. -
Vitamin B-complex (especially B6, B9, B12)
B vitamins help nerve health and red-blood-cell production. Taken in standard multivitamin doses once daily with food. Overuse of certain B vitamins (like B6 in very high doses) can harm nerves, so balance is important. -
Vitamin C
Acts as an antioxidant and supports collagen in blood vessels and connective tissues. Common dose: 250–500 mg once or twice daily. High doses can cause stomach upset and kidney stones in susceptible people. -
Vitamin E
Fat-soluble antioxidant that protects cell membranes from oxidative stress. Usually 15 mg (22 IU) daily is enough; high-dose vitamin E is not routinely recommended because it may increase bleeding risk. -
Zinc
Important for retina and immune system. Small doses (8–11 mg/day in adults) are usually safe; much higher doses can cause copper deficiency and GI upset. -
Coenzyme Q10
Mitochondrial cofactor that may support cellular energy. Typical supplemental doses range 30–100 mg daily with fat-containing food. Side-effects: mild GI discomfort, headache. -
Probiotics
Beneficial bacteria that support gut health and may slightly modulate immunity. Taken as capsules or fermented foods. Side-effects: gas or bloating at the start; serious problems are very rare in healthy people.
Immunity booster / regenerative / stem-cell drug approaches
At the moment, there are no specific immune-booster or stem-cell drugs approved to treat Coloboma of macula-brachydactyly type B syndrome. Below are concepts currently used or researched in related eye diseases; they should only be used when clearly indicated and under specialist care.
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Routine childhood and adult vaccines
Standard vaccinations (for example measles, influenza, pneumonia where recommended) do not treat the syndrome but protect against infections that could further stress health or vision. Doses follow national schedules. Side-effects: mild fever, soreness, very rare serious reactions. -
Gene therapy model – voretigene neparvovec (Luxturna)
This is an FDA-approved gene therapy for a different inherited retinal dystrophy caused by biallelic RPE65 mutations. It uses a viral vector to deliver a working gene copy to retinal cells, given once by subretinal injection.[10] It is not approved for this syndrome, but shows what may be possible in future genetic therapies. -
Experimental retinal cell or stem-cell transplants
Research trials are studying transplantation of retinal pigment epithelium cells or photoreceptor-like cells made from stem cells in some degenerative eye diseases. These aim to replace damaged cells but remain experimental and are not routine care. -
Mesenchymal stem-cell (MSC) trials for eye disease
Some controlled studies are evaluating MSC-derived products to reduce inflammation or support blood vessels in retinal disease. Unregulated “stem-cell clinics” outside trials can be dangerous and should be avoided. -
Biologic immune modulators for associated autoimmune disease
If a person with this syndrome also has a separate autoimmune condition, biologic drugs (like anti-TNF agents) may be used for that disease, not for the coloboma itself. They work by blocking specific immune pathways but can increase infection risk. -
Nutritional and lifestyle immune support
Adequate sleep, balanced diet, regular gentle exercise, and stress-management improve overall immune resilience and healing ability. These are safer and better-proven “immune boosters” than unregulated pills.
Surgeries (procedures and why they are done)
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Retinal detachment repair (pars plana vitrectomy with laser or cryotherapy)
If the retina detaches near the coloboma, emergency surgery removes vitreous gel and seals retinal tears to prevent permanent blindness. It does not fix the original coloboma but can save remaining vision.[6] -
Strabismus (squint) surgery
Adjusting the eye muscles can improve eye alignment, reduce double vision, and help social appearance. It may not improve visual acuity but can make eye contact and orientation easier. -
Cataract extraction
If cataracts form and significantly blur vision, surgery to remove the cloudy lens and insert an artificial lens can maximize whatever vision is left from the macula. -
Hand reconstructive surgery for brachydactyly and syndactyly
Surgeons may separate fused fingers, straighten bent joints, or reshape thumbs to improve grip and fine-motor function. Surgery is usually timed in childhood to match growth and functional needs.[3] -
Toe surgery and footwear optimization
Correction of severe toe deformities can improve shoe fitting, walking comfort, and balance. Sometimes simple tendon releases or bone reshaping are enough.
Prevention strategies
Because this is a genetic syndrome, we cannot fully prevent it, but we can reduce complications and support healthy development:
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Genetic counselling before future pregnancies.
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Avoiding closely related parents (consanguinity) where culturally possible.
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Early eye examinations in newborns with family history.
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Regular follow-up with ophthalmology to detect retinal tears early.
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Protective eyewear during sports and risky activities.
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Safe home design to prevent falls (good lighting, handrails, no loose rugs).
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Healthy pregnancy habits (no smoking, alcohol, or harmful drugs unless prescribed).
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Balanced diet and vitamin D sufficiency for bone and eye health.
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Prompt treatment of eye infections or injuries.
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Psychological and educational support to prevent secondary problems like anxiety and school failure.
When to see doctors
See a doctor or eye specialist urgently if there is:
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sudden loss or shadow of vision
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new flashes of light or many floaters (possible retinal tear or detachment)
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red, painful eye with decreased vision
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severe headache with eye symptoms
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sudden worsening of hand or foot pain, swelling, or inability to move a joint
Regular, planned visits with ophthalmology, orthopaedics/hand surgery, genetics, and rehabilitation should continue even when the person feels “stable,” because subtle changes can be caught early.
Things to eat and things to avoid
What to eat (general eye- and bone-healthy diet):
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Green leafy vegetables (spinach, kale) – rich in lutein and zeaxanthin.
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Orange/yellow vegetables (carrots, pumpkin, sweet potatoes) – natural vitamin A sources.
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Oily fish (salmon, sardines) – omega-3 fats that support retinal cells.
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Eggs – contain lutein, zeaxanthin, and good protein.
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Citrus fruits and berries – vitamin C and antioxidants.
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Nuts and seeds (almonds, sunflower seeds) – vitamin E and healthy fats.
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Dairy products or fortified plant milks – calcium and vitamin D.
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Whole grains – steady energy and fiber.
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Beans and lentils – plant protein and minerals like zinc.
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Plenty of water – supports overall eye and body function.
What to limit or avoid (for general health and eye safety):
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Smoking and second-hand smoke – harms blood vessels and eye tissues.
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Heavy alcohol use – damages nerves and overall health.
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Very salty processed foods – can worsen blood-pressure-related eye risks.
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Sugary drinks and sweets – increase obesity and diabetes risk.
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Deep-fried and trans-fat-rich fast foods – raise inflammation.
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Extremely high-dose “miracle” vitamin products without medical advice.
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Unregulated “stem-cell” or “vision cure” supplements bought online.
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Excessive caffeine drinks that disturb sleep and healing.
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Energy drinks high in sugar and stimulants.
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Diets that cut whole food groups without professional guidance.
Frequently asked questions (FAQs)
1. Is Coloboma of macula-brachydactyly type B syndrome common?
No. It is extremely rare, with only a few families described worldwide. Most doctors never see a case in their whole career.[1]
2. Is it inherited?
Yes, it is usually autosomal dominant, meaning a person with the condition has a 50% chance of passing the gene change to each child.
3. Does the vision always get worse with age?
The central vision is reduced from birth because of the macular coloboma. Some people stay stable for many years; others may lose more vision if complications like retinal detachment occur. Regular eye checks aim to catch problems early.[4][6]
4. Can glasses completely fix the vision?
Glasses can correct refractive errors (short-sightedness, long-sightedness, astigmatism) but cannot rebuild the missing tissue in the macula. They often improve clarity a bit but do not restore normal vision.
5. Does surgery cure the macular coloboma?
No. Eye surgery can repair complications such as retinal detachment or cataract, but it cannot replace the missing macular tissue. Low-vision aids remain important.
6. Can hand surgery make the fingers look “normal”?
Surgery can improve function and appearance but usually cannot make hands completely typical. The main goal is better grip, independence, and comfort, not perfection.
7. Is life expectancy normal?
Based on current reports, life expectancy appears close to normal, because the main problems are vision and limb structure, not vital organs.[1][2]
8. Can children with this syndrome go to regular school?
Yes, many can, especially with early low-vision support, special seating, large-print materials, and occupational therapy for writing and practical tasks.
9. Will a future gene therapy cure this syndrome?
We do not know yet. Gene therapy for other retinal diseases (such as RPE65-related dystrophy) is now approved and shows that gene-based treatment is possible, but there is no specific therapy for this exact syndrome today.[10]
10. Is it safe to try stem-cell treatments advertised online?
No. Many advertised stem-cell “cures” are unregulated and have caused permanent blindness and other serious harms. Only clinical trials approved by ethics committees and regulators are considered safe settings for such research.
11. What kind of doctors should be involved?
A pediatric or general ophthalmologist, inherited retinal disease specialist, hand/orthopaedic surgeon, geneticist, physiotherapist, occupational therapist, and psychologist or counsellor often work together.
12. Can physical exercise make the condition worse?
Normal, supervised activity is usually safe and healthy. Contact sports with risk of eye trauma may need special protection or avoidance as advised by the eye doctor.
13. Are brothers and sisters at risk?
Siblings may be at risk if a parent carries the gene change. Genetic counselling and, if appropriate, testing can clarify this.
14. Can prenatal diagnosis be done?
If the exact gene change is known in the family, some centers can offer prenatal or pre-implantation genetic diagnosis. Availability depends on local laws and resources.
15. Where can families find reliable information?
Trusted sources include rare-disease databases, genetic information centers, and national ophthalmology societies rather than random websites or social media.[1][2][3]
Disclaimer: Each person’s journey is unique, treatment plan, life style, food habit, hormonal condition, immune system, chronic disease condition, geological location, weather and previous medical history is also unique. So always seek the best advice from a qualified medical professional or health care provider before trying any treatments to ensure to find out the best plan for you. This guide is for general information and educational purposes only. Regular check-ups and awareness can help to manage and prevent complications associated with these diseases conditions. If you or someone are suffering from this disease condition bookmark this website or share with someone who might find it useful! Boost your knowledge and stay ahead in your health journey. We always try to ensure that the content is regularly updated to reflect the latest medical research and treatment options. Thank you for giving your valuable time to read the article.
The article is written by Team RxHarun and reviewed by the Rx Editorial Board Members
Last Updated: February 10, 2025.
