Transferase deficiency galactosemia type 1 (often called classic galactosemia) is a rare genetic disease where the body cannot properly break down a milk sugar called galactose. This happens because a liver enzyme named galactose-1-phosphate uridylyltransferase (GALT) is missing or works very poorly. As a result, toxic substances (galactose-1-phosphate, galactose, and galactitol) build up in the blood and organs.
Transferase deficiency galactosemia type 1 (classic galactosemia) is a rare genetic disease where the body cannot safely process a milk sugar called galactose because an enzyme named galactose-1-phosphate uridylyltransferase (GALT) is missing or very low.[1] When a baby with this condition drinks breast milk or regular formula, galactose builds up in the blood and tissues and turns into toxic chemicals (especially galactose-1-phosphate and galactitol). These chemicals can damage the liver, brain, eyes, and other organs, and can be life-threatening in the first days or weeks of life if not treated quickly.[2]
Classic galactosemia is inherited in an autosomal recessive way, which means a child must get a faulty GALT gene from both parents to be affected.[3] Newborn screening programs in many countries test babies for galactosemia soon after birth, so treatment can start before severe damage happens.[4] Even with early treatment, some people develop long-term problems such as learning difficulties, speech problems, movement issues, and ovarian failure in girls, so lifelong follow-up is needed.[1][2]
This disease usually starts in the first days or weeks of life, after a baby drinks breast milk or formula that contains lactose (lactose = glucose + galactose). Without enough GALT, galactose cannot move through the normal “Leloir pathway,” so the sugar gets stuck and becomes harmful to the liver, brain, eyes, and other organs.
Classic galactosemia is inherited in an autosomal recessive way. This means a baby gets one non-working GALT gene from each parent. If it is not found and treated early, the baby can develop feeding problems, liver failure, serious infections (sepsis), and even death. Even with early treatment, some people may still have long-term problems, such as learning difficulties, movement problems, and reduced fertility in females.
Other names
Doctors use several names for transferase deficiency galactosemia type 1. All of the names below refer to the same basic problem: a strong lack of the GALT enzyme.
Other names (synonyms)
Classic galactosemia – the most common term used in clinics and guidelines.
Type 1 galactosemia – shows that this is the type caused by GALT deficiency (type II is GALK, type III is GALE deficiency).
GALT deficiency – short name focusing on the enzyme that is missing.
Galactose-1-phosphate uridylyltransferase deficiency – the full biochemical name of the enzyme problem.
Galactosemia I (GALAC1) – name used in some disease databases.
Types or forms of GALT-related galactosemia
All these forms are due to changes in the same GALT gene, but they differ in how much enzyme activity remains and how severe the disease is.
Classic galactosemia – almost no GALT activity; very severe symptoms in newborn period if not treated.
Clinical variant galactosemia – some GALT activity is present; symptoms may be milder or appear later but can still be serious.
Biochemical variant galactosemia (e.g., Duarte variant) – higher enzyme activity and usually much milder or no symptoms; often found on newborn screening and may not need strict treatment.
Causes
Remember: the true root cause is always a problem in the GALT gene. The items below describe the main genetic cause and different risk factors or genetic situations that can lead to the disease appearing in a child.
Pathogenic variants (mutations) in the GALT gene
The basic cause is a harmful change in both copies of the GALT gene. These variants change the structure of the GALT enzyme so it cannot work or works very poorly. Without working GALT, galactose-1-phosphate builds up and damages cells.Autosomal recessive inheritance
The disease appears when a child receives one faulty GALT gene from each parent. Each parent is usually healthy but is a carrier. When both parents are carriers, each pregnancy has a 25% (1 in 4) chance of classic galactosemia in the baby.Common classic mutations (such as Q188R)
Some variants, like Q188R, are strongly linked with classic, severe disease. These variants cause almost complete loss of enzyme activity. They are seen often in certain populations.Clinical variant mutations (such as S135L)
Other variants, like S135L, may allow a small amount of enzyme activity. They can cause “clinical variant” galactosemia, which may still be serious but sometimes looks slightly milder.Duarte and other biochemical variant alleles (such as N314D)
Some GALT changes, for example N314D (Duarte variant), lead to partial enzyme loss. When combined with a classic allele, they may cause a milder “biochemical variant” form.Compound heterozygosity
Many patients do not have two identical mutations. Instead, they have two different harmful variants (one on each copy of the gene). This is called compound heterozygosity and can still cause classic galactosemia if both variants are severe.Consanguinity (parents related by blood)
In communities where parents are related (for example, cousins), there is a higher chance that both carry the same rare GALT variant. This increases the chance of a child being born with the disease.Family history of galactosemia
Having an older child or close relative with galactosemia shows that the harmful GALT variants are present in the family gene pool. Future pregnancies then carry a known risk of the same disease.Certain ethnic or regional groups with founder mutations
Some populations have “founder” GALT variants that are more common because they came from a shared ancestor. This can increase the disease frequency in that group compared with other populations.Complete loss of enzyme function (null alleles)
Some GALT variants stop the enzyme from being made at all or cause it to break down quickly. These “null” variants usually cause the most severe classic form, with almost no detectable activity in red blood cells.Misfolding of the GALT enzyme
Other variants change one amino acid in the protein, so the enzyme folds the wrong way. Misfolded GALT protein may be unstable or stuck in the wrong part of the cell, leading to low activity.Reduced ability to bind its normal partners (substrate or cofactor)
Some changes affect the active site of the enzyme, so GALT cannot bind galactose-1-phosphate or the nucleotide sugar it needs to work. This functional defect reduces or blocks the chemical reaction.Defects in enzyme transport or stability in liver cells
In some variants, the enzyme is produced but not transported or anchored correctly inside liver cells. The protein may also be quickly destroyed by the cell’s quality-control systems.Combination of a severe and a moderate allele
A child may inherit one very severe allele and one milder allele. The total GALT activity may still be very low, leading to symptoms, but the exact severity can vary depending on the allele pair.Lack of newborn screening or delayed screening
When a region does not have strong newborn screening for galactosemia, babies may continue to drink milk, allowing toxic sugars to build up. This does not cause the mutation, but it makes the genetic problem show early and severely.Unrecognized clinical variant forms
Some babies with partial GALT activity might look only mildly sick at first. If doctors do not suspect galactosemia, diagnosis and diet change may be delayed, allowing more damage.Parents not aware they are carriers
Most carrier parents have no symptoms. Without carrier testing or family history, they may not realize their risk before pregnancy and cannot plan for early testing.Rare de novo variants
In a small number of cases, a new GALT mutation can appear in a child even if it is not seen in either parent’s blood. This is called a de novo event, but it is much less common than inherited variants.Limited access to genetic counseling
When families do not have access to genetic counseling services, they may miss chances to understand carrier status, recurrence risks, and options for prenatal or early testing.Co-existing medical or social factors that delay care
Poverty, remote location, or limited health services can slow diagnosis and treatment. These factors do not cause the gene variant but can worsen the impact of the underlying GALT deficiency.
Symptoms
Feeding problems in the first days of life
Many babies with classic galactosemia develop poor sucking, weak feeding, or refusal of milk soon after starting breast or formula feeds. The baby may seem fussy, feed slowly, or stop feeding entirely, which is often one of the first warning signs.Vomiting and diarrhea
Because the body cannot handle galactose, the gut becomes irritated. Babies often vomit repeatedly and may have loose, watery stools. This can quickly lead to dehydration and weight loss if not treated.Failure to thrive (poor weight gain and growth)
A baby may not gain weight as expected on the growth chart. Clothes may remain loose, and there may be little fat under the skin. This “failure to thrive” happens because the baby is not absorbing food well and is also sick from toxin buildup.Jaundice (yellow skin and eyes)
Liver injury from galactose-1-phosphate buildup can cause jaundice. Parents may notice yellowing of the eyes (sclera) and skin, dark urine, and pale stools. Jaundice that is strong or lasts longer than usual newborn jaundice should be checked for liver disease like galactosemia.Enlarged liver (hepatomegaly)
The liver may become swollen and firm due to fat accumulation, inflammation, and scarring from toxic sugar products. Doctors may feel a large liver when they gently press the baby’s upper abdomen.Bleeding or easy bruising
A damaged liver cannot make enough clotting factors, so the baby may bruise easily or have bleeding from the nose, gums, or injection sites. Sometimes there is serious internal bleeding.Lethargy and sleepiness
Many babies with classic galactosemia seem floppy, weak, and unusually sleepy. They may not wake up well for feeds and may respond slowly to stimulation. This reflects general sickness, low energy, and sometimes low blood sugar or infection.Low muscle tone (hypotonia)
The baby may feel “floppy” when picked up, with poor head control and weak limb movements. This low muscle tone can be a sign that the brain and muscles are not working normally due to toxin build-up.Serious blood infection (sepsis), often with E. coli
Classic galactosemia is famous for causing life-threatening Gram-negative sepsis, often from E. coli. Babies can develop fever or low temperature, fast breathing, poor blood pressure, and shock. This is a medical emergency that needs urgent care.Seizures
Seizures may appear as jerking of the arms or legs, staring spells, or stiffness. They occur because toxins and low blood sugar can irritate the brain. Seizures are a sign of severe illness and need immediate medical attention.Cataracts (cloudy lens in the eyes)
Galactitol builds up in the lens of the eye, drawing in water and making the lens cloudy. Over time, this forms cataracts, which can reduce vision if not treated. Cataracts may improve when galactose is removed from the diet, especially if caught early.Low blood sugar (hypoglycemia)
Liver damage and poor feeding can cause low blood sugar. Babies may be shaky, sweaty, pale, or drowsy, and in severe cases may have seizures. Hypoglycemia is dangerous and must be corrected quickly.Developmental delay and learning difficulties
Even when treated early with a lactose-free diet, some children later show delays in walking, talking, or school learning. This suggests that early damage or ongoing subtle toxicity continues to affect brain development.Speech and language problems
Many people with classic galactosemia have specific speech problems, such as apraxia of speech, slurred speech, or trouble forming clear words. These often need long-term speech therapy.Primary ovarian insufficiency in females
Adolescent girls and women with classic galactosemia have a high risk of primary ovarian insufficiency. They may have irregular or absent periods, hot flashes, and trouble becoming pregnant. This problem may appear even when diet treatment started early.
Diagnostic tests
Physical examination tests
Full newborn physical examination
The first “test” is a careful hands-on exam by a doctor. They check the baby’s appearance, skin color, breathing, heart sounds, feeding, and level of alertness. Signs like jaundice, weak feeding, and poor muscle tone can raise suspicion of galactosemia or other serious metabolic diseases.Growth and weight measurement
The baby’s weight, length, and head size are measured and plotted on a growth chart. Poor weight gain or weight loss in the first weeks of life, together with feeding problems, may suggest failure to thrive due to galactosemia.Abdominal examination for liver and spleen size
The doctor gently feels the belly to see if the liver or spleen are enlarged. A big, firm liver in a jaundiced baby suggests liver injury from conditions like classic galactosemia, and prompts further lab testing.Eye examination with light
Using a light, the doctor looks through the pupil at the lens and the reflection from the retina. A dull or white reflex, or cloudy lens, can suggest cataracts, which are a classic feature of galactosemia and support the need for metabolic testing.
Manual (bedside) tests
Bedside jaundice assessment
Pressing gently on the skin and watching the color return gives a quick sense of jaundice. While not exact, this manual check helps decide whether more exact bilirubin and liver tests are needed in a baby who may have galactosemia.Capillary refill and perfusion check
A doctor presses on a fingernail or skin and counts how long it takes for color to return. Slow refill suggests poor blood flow, which can occur in sepsis or shock due to severe galactosemia, and signals urgent treatment.Basic developmental and tone assessment
Simple bedside maneuvers, such as pulling the baby from lying to sitting, checking head control, and observing spontaneous movements, help the doctor judge muscle tone and early development. Abnormal findings may support suspicion of a metabolic or neurologic disease like galactosemia.
Laboratory and pathological tests
Newborn screening blood spot test (GALT activity / total galactose)
In many countries, a dried blood spot from the baby’s heel is tested for GALT activity and/or total galactose shortly after birth. An “out-of-range” result flags possible classic galactosemia and triggers urgent follow-up testing.Galactose-1-phosphate level in red blood cells
Measuring galactose-1-phosphate in red blood cells confirms that toxic metabolites are elevated. In classic galactosemia, levels are usually very high, and they fall after starting a lactose-free diet.GALT enzyme activity in red blood cells
This is the key diagnostic test. A lab measures how well the GALT enzyme works in red blood cells. In classic galactosemia, activity is absent or almost zero; in variant forms, some activity remains.Genetic testing of the GALT gene
DNA testing can find the specific variants in the GALT gene. This confirms the diagnosis, helps classify the form (classic, clinical variant, biochemical variant), and guides family counseling, carrier testing, and future pregnancy planning.Liver function tests (AST, ALT, bilirubin, albumin, PT/INR)
Blood tests for liver enzymes and clotting show how badly the liver is injured. High liver enzymes and bilirubin, low albumin, and prolonged clotting times are common in untreated classic galactosemia and support the need for urgent metabolic treatment.Complete blood count (CBC) and blood culture
A CBC can show signs of infection or sepsis, such as low white blood cells or low platelets. Blood cultures identify bacteria like E. coli. These tests are vital when a baby with suspected galactosemia looks very sick.Serum electrolytes, glucose, and acid-base status
Blood tests for sodium, potassium, bicarbonate, and pH help detect dehydration, metabolic acidosis, and low blood sugar. These problems often appear in severely ill babies with galactosemia and guide emergency treatment in the hospital.Urine test for reducing substances and galactitol
Simple urine tests can detect “reducing substances,” which may include galactose. More specific tests can measure galactitol. These findings are not enough alone to diagnose the disease but support it when combined with other results.Hormone tests for ovarian function (FSH, LH, estradiol)
In older girls and women with classic galactosemia, blood tests for reproductive hormones can show primary ovarian insufficiency. High FSH and LH with low estradiol suggest the ovaries are failing, which is a known long-term complication.Bone density testing (DXA) with lab checks for calcium and vitamin D
Long-term dietary restrictions and chronic illness may lead to low bone mineral density. A DXA scan, along with blood calcium and vitamin D levels, helps monitor bone health and guide supplements and lifestyle advice.
Electrodiagnostic test
Electroencephalogram (EEG)
If a baby or child with galactosemia has seizures or abnormal movements, an EEG records the brain’s electrical activity. It helps confirm seizures, classify their type, and guide anti-seizure treatment. EEG does not diagnose galactosemia itself but checks one of its serious complications.
Imaging tests
Abdominal ultrasound
An ultrasound scan of the abdomen uses sound waves to look at the liver and other organs. It can show enlarged liver or spleen, fatty changes, and other damage linked to galactosemia. Ultrasound is painless and very helpful in monitoring liver disease.Brain MRI (and other neuroimaging)
In children with long-term neurological problems, a brain MRI can show structural changes, white matter abnormalities, or other injury patterns. These findings support the understanding that, even with diet treatment, classic galactosemia can cause brain changes over time.
Non-pharmacological treatments (therapies and others)
There is currently no cure and no FDA-approved medicine that fixes the enzyme defect in classic galactosemia, so non-drug treatments are the main and most important care.[5][6] Almost everything centres on strict diet and long-term developmental and medical support.
1. Immediate switch to galactose-free infant feeding
As soon as galactosemia is suspected, breast milk and standard cow’s-milk formula are stopped and replaced with soy-based or elemental (amino-acid) formula that contains no lactose or galactose.[2][4] This quickly removes the main external source of galactose and helps reverse liver failure, vomiting, and poor feeding in newborns, often within days.
2. Lifelong galactose-restricted diet
People with classic galactosemia must avoid foods containing lactose and galactose for life, including regular milk, yoghurt, soft cheeses, and most dairy-based processed foods.[2][4] This diet lowers toxic galactose-related chemicals, protects the liver, reduces risk of cataracts, and remains the standard of care worldwide, even though it does not fully prevent long-term complications.
3. Specialist metabolic dietitian support
A metabolic dietitian designs a safe meal plan that removes lactose and galactose but still provides enough protein, calories, vitamins, and minerals, especially calcium and vitamin D (because dairy is cut out).[4][7] The dietitian teaches label-reading, suggests safe alternatives, and regularly reviews growth, bone health, and blood test results, adjusting the plan as the child grows.
4. Regular follow-up in a metabolic clinic
Children and adults with galactosemia benefit from regular visits with a metabolic team (doctor, nurse, dietitian, psychologist, therapist).[1][2] These visits track growth, liver function, hormone levels, development, school progress, and bone health, and help detect problems early so they can be managed before becoming severe.
5. Early speech and language therapy
Many people with classic galactosemia develop speech problems such as verbal dyspraxia (difficulty planning mouth movements to speak).[1] Early, intensive speech therapy helps children learn clearer pronunciation, improve understanding and expression, and reduce frustration and social problems linked to communication issues.
6. Occupational therapy (OT)
Occupational therapists help with fine motor skills (such as writing, using buttons, and feeding), attention, and daily living skills when developmental coordination or learning problems are present.[1][2] OT uses practice, play, and environmental adaptations to improve independence at home and school.
7. Physiotherapy and motor training
Some people develop balance or movement problems and may have tremor or coordination difficulties.[1][11] Physiotherapists design exercises to strengthen muscles, improve balance and coordination, and support safe participation in sports and physical play, which also supports bone health.
8. Educational and learning support
Children with galactosemia may have learning difficulties or specific problems with language, memory, or attention.[1][2] Educational psychology assessments and special education plans (individual education plans, classroom aids, extra time on exams) help match teaching methods to the child’s needs and improve school success.
9. Psychological counselling and family support
Living with a rare, lifelong condition and following a strict diet can cause stress, anxiety, or low mood for both patients and families.[5][11] Counselling, family therapy, and peer support groups help people cope emotionally, handle social situations involving food, and plan for adult life, work, and relationships.
10. Genetic counselling
Genetic counsellors explain how galactosemia is inherited, what “carrier” means, and the chance of having another affected child.[3] They also discuss options such as carrier testing of relatives, prenatal diagnosis, and family planning choices, helping parents make informed decisions based on accurate information.
11. Newborn screening and early diagnosis in future pregnancies
In many regions, newborn screening includes GALT deficiency, allowing diagnosis in the first days of life.[4][23] Parents of one affected child are encouraged to ensure all future babies are screened promptly and to alert the team so formula changes can happen immediately if results are positive.
12. Regular blood and urine monitoring
Doctors monitor markers like galactose-1-phosphate, galactitol, liver enzymes, and sometimes bone and hormone tests to track control of the disease and detect complications.[1][19] Although “endogenous” (internally produced) galactose means levels are never zero, tracking trends helps guide diet strictness and overall management.
13. Endocrine and fertility follow-up (especially in females)
Many girls and women with classic galactosemia develop primary ovarian insufficiency (POI), so they need regular hormone, menstrual, and bone checks with an endocrinologist or gynaecologist.[1][11] Early detection allows timely hormone treatment, fertility counselling, and bone-protective measures.
14. Bone health strategies and weight-bearing exercise
Because dairy is restricted and hormones may be low, people with galactosemia risk weak bones.[4][8] Weight-bearing activities (walking, running, dancing, jumping exercises) plus adequate calcium and vitamin D (by diet or supplements) help build and maintain stronger bones across life.
15. Infection prevention and vaccination
Newborns with untreated galactosemia are at high risk for serious infections (especially E. coli sepsis).[1][19] Strict early diet, breastfeeding avoidance, and complete routine vaccinations, along with rapid medical review for fever, are key non-drug ways to prevent or limit severe infections over time.
16. Family education and written emergency plans
Families are taught to recognise signs of acute illness (poor feeding, vomiting, lethargy, jaundice, fever) and to seek urgent care if these appear.[3][23] Many centres give written “emergency letters” explaining the condition and the need to avoid lactose-containing IV fluids and drugs, which can be shown in any hospital.
17. Support groups and patient organisations
Joining galactosemia patient groups (local or online) connects families with others who face the same challenges.[5][11] These groups share practical diet tips, information about research, and emotional support, which can reduce isolation and help with everyday problem-solving.
18. Transition planning to adult care
As teenagers grow older, the team prepares them to move from paediatric to adult metabolic services.[2][24] Education about self-management, reproductive health, career planning, and mental health makes the change smoother and reduces the chance of dropping out of follow-up.
19. Pregnancy planning and high-risk obstetric care
Women with galactosemia who become pregnant need careful planning with metabolic and high-risk obstetric teams.[1][11] Although the baby is not directly harmed by the mother’s diet, the mother’s health, hormones, bone status, and diet must be optimised, and genetic risks for the baby should be discussed.
20. Avoidance of galactose-containing medications
Some liquid medicines and laxatives (for example lactulose) contain galactose and are contraindicated in galactosemia.[8][9] Pharmacists and doctors must always check ingredients and choose alternatives, and families should be taught to remind health professionals about the condition before any new medicine is given.
Drug treatments (supportive and evidence-based)
Very important: there are currently no FDA-approved drugs that correct the GALT enzyme defect or cure classic galactosemia.[5][6][14] Medicines are used to treat complications (such as infections, seizures, or hormone problems) or to support nutrition and bone health. All dosing must be decided by a doctor; this information is general and not for self-treatment.
1. Intravenous (IV) fluids and electrolytes in acute crisis
When a newborn with undiagnosed galactosemia becomes very sick (vomiting, dehydration, shock), doctors give IV fluids with appropriate sugars and salts to stabilise blood pressure and restore circulation while stopping galactose intake.[2][3] Fluids are chosen carefully to avoid lactose-containing products and to correct acidosis and electrolyte imbalances.
2. Broad-spectrum IV antibiotics for sepsis
Because untreated galactosemia greatly increases the risk of serious infections like E. coli sepsis, doctors often start broad-spectrum IV antibiotics as soon as sepsis is suspected.[3][19] Early antibiotic treatment, combined with diet change and supportive care, is life-saving in many infants.
3. Vitamin K for bleeding problems
Liver failure and poor nutrition can cause blood-clotting problems in newborns. Vitamin K injections (an FDA-approved treatment for bleeding risk in newborns) are often used to correct clotting and prevent serious bleeding while the diet is changed and liver function improves.[3]
4. Ursodeoxycholic acid for cholestatic liver disease
Some babies develop cholestasis (poor bile flow) and jaundice. Ursodeoxycholic acid, a bile acid medicine, may be used to improve bile flow and liver tests in cholestatic liver disease in many conditions, including galactosemia-related liver damage.[3] The drug works by protecting liver cells and making bile less toxic.
5. Calcium supplements
Because dairy is restricted, most patients need calcium supplements to protect bone health.[4][8] Calcium salts (like calcium carbonate) are FDA-approved for prevention and treatment of low calcium and osteoporosis; in galactosemia they are used to replace the calcium that would usually come from milk and help keep bones strong.
6. Vitamin D supplements
Vitamin D helps the gut absorb calcium and keeps bones and teeth strong. Vitamin D drops or tablets are often prescribed for people with galactosemia, especially if blood levels are low, contributing to prevention of rickets in children and osteoporosis in adults.
7. Multivitamin preparations
A daily multivitamin may be recommended to cover nutrients that might be slightly lower in a restricted diet, such as some B vitamins and trace minerals.[4][24] These products are widely licensed and help ensure the child grows well, especially if they are picky eaters or have feeding difficulties.
8. Hormone replacement therapy (HRT) for primary ovarian insufficiency
Many girls and women with classic galactosemia develop POI and may have absent or irregular periods and low oestrogen levels.[1][11] When appropriate, doctors may prescribe oestrogen-containing HRT or combined hormonal contraceptives to support puberty, maintain bone health, and manage menstrual cycles, following standard endocrine guidelines.
9. Bisphosphonates for severe osteoporosis
If bone density scans show significant osteoporosis with fractures, doctors may consider bisphosphonate drugs (for example, alendronate) used in many conditions to strengthen bone.[4] These drugs slow bone breakdown and, together with calcium, vitamin D, and exercise, can reduce fracture risk in carefully selected patients.
10. Antiepileptic drugs for seizures
Some individuals with galactosemia develop seizures due to brain injury or metabolic instability.[1][3] Standard antiepileptic medicines such as levetiracetam or valproate may be prescribed to control seizures, with careful choice to avoid galactose-containing excipients in liquid formulations.
11. Thyroid hormone (levothyroxine) when hypothyroidism is present
Thyroid problems are not universal but can occur in some metabolic and endocrine disorders. When blood tests confirm hypothyroidism, levothyroxine is prescribed to normalise thyroid hormone levels, improve growth, and support metabolism according to endocrinology protocols.
12. ADHD or anxiety medications when needed
Some patients develop attention, behavioural, or anxiety disorders, and may benefit from standard medicines such as stimulants for ADHD or SSRIs for anxiety/depression, always prescribed and monitored by specialists.[5] These medicines do not treat galactosemia itself but can improve quality of life and learning.
13. Antiemetic drugs (for example, ondansetron) for severe vomiting
During acute illness or dehydration, doctors may use anti-nausea medicines such as ondansetron to control vomiting and allow oral rehydration, while also treating the underlying cause and managing galactose intake.
14. Analgesics (pain relievers)
Common pain and fever medicines (such as paracetamol/acetaminophen) can be used when needed, but doctors and pharmacists must ensure the formulation does not contain lactose or galactose as an excipient.[6][9] Correct dosing and careful checking of ingredients are essential for safety.
15. Proton pump inhibitors (PPIs) or reflux medicines if needed
If a child has severe reflux or oesophagitis, medicines like PPIs may be prescribed, following general paediatric guidelines, while still maintaining the galactose-restricted diet and checking excipients.
16. Iron supplements for anaemia
If tests show iron-deficiency anaemia, iron supplements are used to rebuild iron stores and improve energy.[3] As with other medicines, the care team chooses iron preparations that do not contain lactose or galactose.
17. Experimental aldose reductase inhibitor: govorestat (AT-007)
Govorestat is an investigational aldose reductase inhibitor being developed to reduce galactitol, a toxic sugar alcohol that builds up in galactosemia.[7][8] It has received orphan drug and fast-track designations, and trials show reduced galactitol and possible neurological benefits, but in 2024 the FDA did not approve it yet, so it remains research-only.
18. Other investigational small-molecule therapies
Researchers are exploring other small-molecule drugs to improve galactose metabolism or protect cells from toxicity (for example, other aldose reductase inhibitors or metabolic modulators), but none are yet approved, and all use is restricted to clinical trials.[1][7][14]
19. Supportive medications for clinical trial participation
Participants in gene therapy or mRNA therapy trials may receive standard supportive medicines (for example, steroids to manage immune reactions, analgesics, or anti-nausea drugs) according to the trial protocol.[1][7] These therapies remain investigational and are only used under strict research supervision.
20. Emergency medicines in intensive care
In rare, very severe cases (for example, shock or liver failure), intensive-care medicines such as vasopressors, blood products, or anti-convulsants are used according to standard critical-care practice, while strictly avoiding lactose-containing products.[3] These medicines stabilise the patient but do not change the underlying genetic disease.
Dietary molecular supplements
(Always prescribed and monitored by a doctor or dietitian, not self-started.)
1. Calcium
Calcium supplements help replace calcium lost from the diet when dairy is removed and support normal bone and tooth mineralisation.[4][8] They are usually given daily in child- or adult-appropriate doses and are especially important in people with low bone density or hormonal problems that weaken bones.
2. Vitamin D
Vitamin D improves calcium absorption from the gut and is essential for bone growth and immune function.[4] People with galactosemia often need vitamin D drops or tablets because dietary sources are limited and sun exposure may be low; levels are checked by blood tests and doses adjusted.
3. Vitamin K2 (where appropriate)
In some settings, vitamin K2 is considered to support proper calcium use in bones and reduce abnormal calcium deposition in vessels.[8] Evidence in galactosemia is limited, so it is used only when a specialist recommends it, as part of a broader bone-health plan.
4. B-complex vitamins (including folate and B12)
B vitamins support energy production and nervous-system function. A B-complex or multivitamin helps ensure adequate intake when diet variety is limited, and may be useful if there are neurological symptoms or eating difficulties; doses are kept within standard recommended ranges.
5. Omega-3 fatty acids
Omega-3 fats (from fish-oil or algae-oil supplements) support brain and eye development and may help with inflammation.[1] They can be considered if dietary intake of oily fish is low, but should be chosen carefully (checking for safe excipients) and used under professional advice.
6. Choline
Choline is important for brain development, liver health, and cell membranes. Some metabolic teams consider choline-rich foods or supplements if dietary intake is low, hoping to support neurodevelopment, although specific evidence in galactosemia is still emerging.
7. Magnesium
Magnesium supports muscle and nerve function and works with calcium in bone. It may be supplemented when dietary intake is low or when certain medicines (like diuretics) increase losses, always with monitoring to avoid excess.
8. Prebiotic fibre
Prebiotic fibres (such as inulin) feed healthy gut bacteria and may help bowel health and immunity. In a restricted diet, adding safe high-fibre foods or prebiotic supplements can support gut function, but products must be checked to ensure they are free from lactose or galactose.
9. Antioxidant vitamins (vitamin C and E)
Antioxidants help neutralise harmful free radicals. Some researchers are interested in whether antioxidant support might protect cells from metabolic stress in classic galactosemia, but strong evidence is limited and supplements should not exceed standard safe doses.
10. Protein supplements (when needed)
If a child struggles to meet protein needs (for example, due to feeding issues), protein powders or specialised formulas that are lactose-free may be used to support growth and muscle mass. Dietitians choose products carefully to ensure they are safe for galactosemia.
Immunity booster / regenerative / stem cell
At present there are no approved stem-cell or gene-therapy drugs for galactosemia. The approaches below are research-only and must not be used outside clinical trials.
1. Experimental AAV gene therapy (for example, JAG101)
Preclinical studies of adeno-associated virus (AAV) gene therapy, such as JAG101, deliver a healthy GALT gene to liver and brain cells in animal models.[8] These one-time treatments increased GALT activity and reduced toxic metabolites in mice, suggesting a regenerative effect on the enzyme defect, but human trials are still in early stages or preclinical.
2. Experimental mRNA therapy
mRNA therapy delivers laboratory-made GALT mRNA into cells so they can temporarily produce the missing GALT enzyme.[6][10][16] In mouse models, repeated doses normalised disease markers and improved motor function, showing a promising but still experimental way to “replace” the enzyme without altering DNA.
3. Experimental aldose reductase inhibitor govorestat (AT-007)
Govorestat aims to reduce formation of galactitol, a toxic alcohol that may damage nerves and the brain.[7][3] Trials show it lowers galactitol levels and may improve daily functioning in children, but the FDA has not approved it yet, and concerns about trial data have led to delays and a recent rejection, so it remains investigational only.
4. Future combined gene + metabolic protection strategies
Researchers are exploring combinations of gene therapy or mRNA therapy with protective small molecules to both fix GALT activity and shield cells from remaining toxic metabolites.[1][10] These advanced strategies are still in laboratory or early trial phases and are not available for routine clinical use.
5. Supportive immune protection with vaccination
Although not a “booster drug,” complete and on-time vaccination acts as a powerful immune support, protecting children with galactosemia—who may be more fragile in early life—from preventable infections and sepsis.[3][19] This is a key part of standard care and should always follow national schedules.
6. (Theoretical) cell-based liver therapies
Liver or hepatocyte cell transplantation has been discussed in the medical literature as a possible future way to provide cells with normal GALT activity in severe metabolic diseases, but for galactosemia this remains theoretical and experimental, with no established protocols.[1][14] Any such approach would carry major risks and would only be considered in tightly controlled research settings.
Surgeries (procedures and why they are done)
1. Cataract extraction surgery
If cataracts develop in the lens of the eye due to galactitol buildup and do not improve after diet treatment, eye surgeons may remove the cloudy lens and replace it with an artificial one.[2] This restores clearer vision and prevents long-term visual impairment.
2. Liver transplantation (rare, for end-stage disease)
In exceptional cases of severe, irreversible liver failure despite early treatment, liver transplantation may be considered.[3] This major surgery replaces the damaged liver with a donor liver and can correct liver failure, but does not fully cure galactosemia in other organs or reverse established brain changes.
3. Gastrostomy tube placement
If a child has severe feeding problems or cannot safely take enough galactose-free formula or food by mouth, surgeons may place a small tube directly into the stomach (PEG or gastrostomy tube).[3] This helps deliver safe nutrition reliably while continuing oral-feeding therapy.
4. Orthopaedic surgery for fractures or deformities
In cases of severe osteoporosis with fractures or bone deformities, orthopaedic surgery may be needed to stabilise bones, correct alignment, or relieve pain.[4] This is combined with strong bone-health management (diet, supplements, exercise, and medicines) to prevent further damage.
5. Fertility-related procedures (for example, assisted reproduction)
Women with primary ovarian insufficiency may sometimes use assisted reproduction techniques like IVF using donor eggs, which involve gynaecological procedures and hormone stimulation.[1][11] These approaches help some women with galactosemia become parents while managing the condition safely under specialist supervision.
Key preventions
Newborn screening for every baby where available to detect galactosemia before symptoms appear.
Immediate switch to galactose-free formula as soon as galactosemia is suspected, without waiting for full confirmation.
Lifelong strict avoidance of lactose and galactose–rich foods, especially dairy products and foods with hidden milk ingredients.
Careful checking of medicine ingredients to avoid lactose/galactose-containing products such as lactulose.
Regular follow-up in a metabolic clinic to catch problems early and adjust diet and supplements.
Complete routine vaccination to prevent serious infections that can be more dangerous in metabolic diseases.
Family education so parents and older patients recognise danger signs (poor feeding, vomiting, lethargy, fever, jaundice) and seek rapid care.
Bone-health protection with adequate calcium/vitamin D, exercise, and hormone support when needed.
Genetic counselling and carrier testing for family planning and early testing of future pregnancies and newborns.
Participation in natural-history or treatment studies, where appropriate, to support better future guidelines and therapies.
When to see doctors
Parents should seek immediate emergency care for a newborn or infant who shows poor feeding, vomiting, extreme sleepiness, breathing problems, jaundice, fever, or signs of shock (cold skin, weak pulses, very low energy), especially in the first weeks of life.[3] These may be signs of untreated galactosemia or a serious infection and need urgent hospital treatment.
Children and adults with diagnosed galactosemia should see their metabolic or family doctor urgently if they develop new jaundice, persistent vomiting, severe abdominal pain, seizures, sudden behaviour change, or unexplained weight loss.[2] Regular planned follow-ups (often at least once a year) are also essential, even when the person feels well, to monitor growth, learning, hormones, and bones.
Teenagers and adults, especially women, should seek specialist review for delayed puberty, irregular or absent periods, fertility concerns, bone pain, or repeated fractures, because these may signal treatable hormone or bone problems linked to galactosemia.[1][11]
What to eat and what to avoid
Eat: lactose-free or soy-based infant formulas and plant-based milks that are confirmed galactose-free.
Eat: fresh fruits and most vegetables, which naturally contain very little galactose and are generally safe in standard guidelines.
Eat: plain grains (rice, wheat, oats, corn), breads and cereals without milk ingredients, and safe pasta and noodles.
Eat: fresh meat, poultry, fish, and eggs, which provide high-quality protein and are naturally lactose-free.
Eat (with expert guidance): some aged hard cheeses or special low-galactose products may be allowed in small amounts under strict dietitian supervision, depending on local guidelines and the individual’s status.
Avoid: breast milk and regular cow’s-milk formulas (unless a special individual plan is made by specialists), because they are rich in lactose and galactose.
Avoid: fresh milk, yoghurt, cream, soft cheeses, ice cream, milkshakes, and most dairy-based desserts.
Avoid: foods with ingredients like milk, lactose, whey, casein, milk solids, and many “cream” sauces or instant soups unless the label and dietitian confirm they are safe.
Avoid: medicines and supplements that contain lactose or galactose (for example some tablets, chewables, or syrups, and lactulose laxative), unless the metabolic team confirms they are acceptable.
Avoid: self-changing diet without professional advice, because overly strict or poorly planned restriction can lead to malnutrition, while too liberal intake can increase long-term complications.
Frequently asked questions (FAQs)
1. Is classic galactosemia the same as “lactose intolerance”?
No. Lactose intolerance is a common digestive problem where people lack lactase in the gut and get bloating and diarrhoea, but it is not usually dangerous. Classic galactosemia is a serious genetic disease affecting internal sugar metabolism and can cause life-threatening illness in newborns if untreated.[2][4]
2. Can diet alone cure galactosemia?
Dietary galactose restriction is life-saving and greatly reduces acute problems, but it does not fully cure the disease because the body still makes some galactose internally. Many people still develop long-term complications, so diet plus lifelong monitoring and support are needed.[0][5]
3. Are there any approved medicines that fix the GALT enzyme?
At this time, no medicine has been approved by the FDA that directly corrects GALT deficiency.[5][6] Several approaches, including gene therapy, mRNA therapy, and the drug govorestat, are under study in clinical trials but remain experimental.
4. What is the outlook for a baby diagnosed early?
If galactosemia is diagnosed through newborn screening and a galactose-free diet is started immediately, most babies survive and avoid severe liver failure or sepsis.[3][23] However, they still need long-term follow-up because learning, speech, movement, and fertility issues can still occur.
5. Will my child be able to go to regular school?
Many children with galactosemia attend mainstream schools, but some need extra support for speech, learning, or attention.[1][2] Early therapy, educational planning, and good communication between families, teachers, and the medical team improve school outcomes.
6. Can a person with galactosemia play sports?
Yes, in most cases. Physical activity is encouraged for general health and strong bones, as long as the child is medically stable and follows the diet.[4][8] Any specific limitations should be discussed with the doctor, especially if there are bone or heart issues.
7. Is pregnancy safe for women with galactosemia?
Pregnancy is possible but may be challenging, particularly because of primary ovarian insufficiency in many women.[1][11] Pre-pregnancy counselling with metabolic and fertility specialists is important to assess hormone status, bone health, and genetic risks and to plan safe care.
8. Can siblings or relatives be carriers?
Yes. Because the condition is autosomal recessive, parents are usually carriers, and siblings or other relatives may also carry one faulty GALT gene.[3] Carrier testing and genetic counselling help families understand their own risk and future reproductive choices.
9. Will my child outgrow galactosemia?
No. Classic galactosemia is lifelong because the genetic change in the GALT gene does not go away.[3] Diet and supportive care control the disease, but people must continue precautions and medical follow-up throughout life.
10. Are small amounts of galactose ever allowed?
Some guidelines allow carefully measured amounts of free galactose from certain low-galactose foods (for example, some aged cheeses) in older children or adults, but this must be planned by a metabolic team and varies between centres.[0][8][18] Families should never change the diet on their own.
11. How is galactosemia different from galactokinase or epimerase deficiency?
All three affect galactose metabolism but at different enzyme steps. Classic galactosemia (GALT deficiency) is usually the most severe form and causes liver failure and sepsis in newborns, while galactokinase deficiency mainly causes cataracts and epimerase deficiency can be milder or variable.[7]
12. Can adults with galactosemia live independently?
Many adults live independently, work, and have relationships, but some need support for learning, mental health, or daily organisation.[5][11] Good transition planning in adolescence and continued access to adult metabolic services make independence more successful.
13. Why do some problems appear even with a perfect diet?
The body makes some galactose itself (“endogenous” production), so toxic chemicals may still form even when dietary galactose is very low.[5][0] Also, early damage before diagnosis and complex effects on brain development mean that diet alone cannot fully prevent all complications.
14. Is research active in galactosemia?
Yes. There is active research into gene therapy, mRNA therapy, aldose reductase inhibitors like govorestat, better diet guidelines, and long-term outcomes.[1][6][7][10][14] Patient organisations and registries play a key role in supporting this research.
15. Where can families find reliable information and support?
Reliable information is available from reputable hospital websites, national metabolic centres, and dedicated galactosemia foundations and patient groups, which provide education, guidelines, and community support.[4][5][11] Healthcare teams can guide families to trusted resources in their region.
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: January 27, 2025.
