Bosma Arhinia Microphthalmia Syndrome

Bosma arhinia microphthalmia (BAM) syndrome is an extremely rare genetic disorder that has been reported in fewer than 100 patients worldwide in the past century. It is defined by three major features: 1) complete absence of the nose, 2) eye defects, and 3) absent sexual maturation. The specific symptoms and severity of the disorder can vary from one person to another. For example, eye problems can range from absent tear ducts (the small tubes that carry tears from the eyes to the nose) to very small eyes with blindness. [rx]Boys with BAM syndrome may be born with underdeveloped genitals (small penis and/or testes that have not descended properly into the scrotum). If a girl with BAM syndrome has problems with her reproductive system, it will only become apparent in her teenage years when she does not develop breasts or have menstrual periods. The nose and eye problems typically require surgery, and the reproductive problems can be treated with hormones (testosterone or estrogen replacement). Despite the severe facial problems, patients typically have normal to above average intelligence and live happy, productive lives. The only known genetic cause of BAM syndrome is a change in the gene SMCHD1. In the majority of cases, this change occurs spontaneously in the egg or sperm cell and is not inherited from the parents.[rx]

Bosma Arhinia Microphthalmia Syndrome (BAMS) is a rare genetic condition that affects the development of a person’s nose and eyes. In this article, we’ll provide a straightforward explanation of BAMS, including its types, causes, symptoms, diagnostic tests, treatments, and relevant drugs.[rx]

Types of BAMS

BAMS is generally classified into two types:

1. Isolated Arhinia: This type of BAMS primarily involves the absence or underdevelopment of the nose.
2. Arhinia with Microphthalmia: In addition to nasal issues, individuals with this type also have small or underdeveloped eyes.

Causes of BAMS

Most genetic diseases are determined by the status of the two copies of a gene, one received from the father and one from the mother. Dominant genetic disorders occur when only a single copy of an abnormal gene is necessary to cause a particular disease. The abnormal gene can be inherited from either parent or can be the result of a new mutation (gene change) in the affected individual. The risk of passing the abnormal gene from an affected parent to an offspring is 50% for each pregnancy. The risk is the same for males and females.[rx]

Researchers believe that having a change in SMCHD1 is necessary but not sufficient to develop BAM syndrome. This is because there are families, for example, where a child with BAM inherited a change in SMCHD1 from his mother who has a very mild form of BAM (for example, no sense of smell but no other defects) or has no medical problems at all. This suggests that the child has a change in a second critical gene, which may have occurred spontaneously or may have been inherited from the other parent, in this example, the father. This type of inheritance, called digenic inheritance, occurs when a change in more than one gene is required to cause disease. Researchers are still trying to identify these other genes.[rx]

The SMCHD1 protein is a gene repressor. This means it has the ability to turn other genes off. It is possible that the changes that occur in SMCHD1 in patients with BAM syndrome cause other genes that are important for developing a normal nose and eyes to be turned off at the wrong time. However, more research is needed to understand how changes in SMCHD1 activity cause BAM syndrome.[rx]

Several of the same changes in SMCHD1 that cause BAM have also been shown to cause a rare form of muscular dystrophy, called facioscapulohumeral muscular dystrophy type 2 (FSHD2; see NORD database). FSHD2 patients have not been reported to have any nose, eye, or reproductive problems, and researchers are still trying to understand if some BAM patients will develop signs of FSHD2 as adults, since FSHD2 is an adult-onset condition, with an average age of onset of 26 years.[rx]

There are no known environmental exposures during pregnancy that cause BAM. However, studies in animals have suggested that high blood sugar, alcohol, and retinoic acid may cause holoprosencephaly, a severe congenital disorder whose features may overlap with those of BAM (e.g., absent nose, anophthalmia or microphthalmia, cleft lip or cleft palate, hormone problems).[rx]

BAMS is primarily caused by genetic mutations. Here are some key points about its causes:

1. Genetic Mutations: BAMS is typically associated with changes in certain genes, although the exact genes involved may vary from person to person.
2. Spontaneous Mutations: In some cases, BAMS can occur as a result of random genetic mutations, even if there’s no family history of the condition.
3. Inheritance: BAMS can be inherited from one or both parents if they carry the mutated gene.

Symptoms of BAMS

The symptoms of BAMS can vary from person to person, but they often include:

1. Absence of Nose: Individuals with BAMS may be born without a visible nose or with a very small, underdeveloped one.
2. Small or Missing Eyes: Those with Arhinia with Microphthalmia may have tiny or absent eyeballs.
3. Breathing Difficulties: Nasal issues can lead to difficulties in breathing and require special medical attention.
4. Facial Differences: BAMS can cause distinct facial features, including a flat nasal bridge and a small or underdeveloped midface.
5. Hearing Problems: Some individuals with BAMS may experience hearing difficulties due to the underdeveloped ears.

Children with BAM syndrome may have problems with vision and their eyes. This includes missing eyes (anophthalmia), abnormally small eyes (microphthalmia), coloboma, cataracts, and absent or narrow tear ducts. In a study of nearly 40 patients with BAM syndrome, 77% of patients had anophthalmia or microphthalmia, 79% had coloboma, 53% had cataracts, and nearly all had missing or narrow tear ducts. Six patients had no vision problems. There can be loss of vision with age.[rx]

• A coloboma is a cleft in or failure to close the eyeball during fetal development. This can result in a keyhole-shaped pupil (iris coloboma) and/or abnormalities in the retina, macula or optic nerve. Coloboma of the retina or optic nerve may cause vision loss, including blind spots, problems with depth perception or legal blindness. Many children with coloboma are sensitive to bright light. They may experience retinal detachment over time.[rx]

• A cataract is a clouding of the lens of the eye (which is normally clear) at birth. Cataracts can cause poor vision but eye doctors can do surgery to fix them.

• Tear ducts normally drain tears from the eyes to the nose. If tear ducts are absent, patients may have excessive tearing. If tear ducts are narrow, bacteria may collect in them, causing infections. Tear ducts can be opened up with surgery.[rx]

Other common facial problems include cleft lip or cleft palate, abnormal external ears (too large or too small), and crowded or missing teeth.

Diagnostic Tests for BAMS

Arhinia is apparent at birth and can sometimes be suspected prenatally. A medical geneticist, pediatrician, or other pediatric subspecialist should do a complete physical exam and order tests to look for the two other major features of BAM, eye defects and genital/hormone defects. Molecular genetic testing for changes in the SMCHD1 gene that are associated with BAM is available at specialized laboratories.[rx]

Diagnosing BAMS usually involves a combination of medical assessments and genetic testing. Here are some common diagnostic tests:

1. Physical Examination: Doctors will examine the infant’s face and nasal passages to identify any abnormalities.
2. Imaging: X-rays or MRIs may be performed to assess the facial and cranial structures.
3. Genetic Testing: A blood sample can be analyzed to detect specific genetic mutations associated with BAMS.
4. Family History: Information about the family’s medical history can also be crucial in making a diagnosis.

Treatments for BAMS

Although children with BAM may require intensive medical support early in life because of difficulty breathing and feeding, they usually become healthy and productive citizens with normal life spans. Many of the structural abnormalities (choanal atresia, cleft palate, etc.) can be surgically corrected and new technologies are allowing surgeons to create much more cosmetically appealing nasal prostheses for these children. [rx]Two groups have published papers on a custom-made nasal implant made with a 3D printer. Most patients will require ongoing medical care from a team of medical and surgical sub-specialists, including plastic or maxillofacial surgeons, ophthalmologists (eye doctors), and endocrinologists (hormone doctors). Psychosocial support for the entire family is essential as well. Genetic counseling may be of benefit for affected individuals and their families. Due to the rarity of BAM, there are no standardized treatment protocols or guidelines for affected individuals.[rx]

BAMS doesn’t have a cure, but there are several treatments and interventions available to manage its symptoms and improve the individual’s quality of life. Here are some common treatments:

1. Surgical Reconstruction: Depending on the severity of the condition, surgeries may be performed to create a functional nose and improve facial appearance.
2. Prosthetic Nose: In cases where complete nasal reconstruction is not possible, a prosthetic nose can be custom-made to enhance appearance and help with breathing.
3. Vision Correction: Individuals with Microphthalmia may benefit from vision correction procedures or specialized eyeglasses.
4. Hearing Aids: If hearing problems are present, hearing aids can be used to improve auditory function.
5. Speech Therapy: For those with speech difficulties due to facial abnormalities, speech therapy can be beneficial.

Drugs for BAMS

While there are no specific drugs to treat BAMS itself, certain medications may be prescribed to manage related symptoms and complications. Here are some examples:

1. Pain Relief Medications: These may be prescribed after surgical procedures to manage pain and discomfort.
2. Antibiotics: Infections in the nasal area or ears may require antibiotic treatment.
3. Eye Drops: Individuals with Microphthalmia may need specialized eye drops to maintain eye health.
4. Nasal Sprays: Nasal sprays can help with breathing difficulties and congestion.

In Conclusion

Bosma Arhinia Microphthalmia Syndrome is a rare genetic condition that affects the nose and eyes. While it can present challenges, individuals with BAMS can lead fulfilling lives with the help of medical interventions, surgical procedures, and supportive care. Early diagnosis and a comprehensive treatment plan can make a significant difference in their overall well-being. If you suspect your child may have BAMS or have a family history of the condition, consult a healthcare professional for proper evaluation and guidance.

 

Disclaimer: Each person’s journey is unique, treatment plan, life style, food habit, hormonal condition, immune system, chronic disease condition, 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. 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. Thank you for giving your valuable time to read the article.

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