Deficiency of uridine diphosphate-glucose–hexose-1-phosphate uridylyltransferase means that the body is missing or has very low activity of an enzyme called galactose-1-phosphate uridyltransferase (GALT). This enzyme normally helps change the milk sugar galactose into a safe form that the body can use for energy. When the enzyme does not work, harmful sugar chemicals build up in the blood, liver, brain, eyes, and kidneys. This condition is also called classic galactosemia and it is an inborn (from birth) error of metabolism. It is inherited in an autosomal recessive way, which means a baby gets one changed gene from each parent. If it is not treated quickly, it can cause severe liver disease, infections, and even death in newborns.
Classic galactosemia (deficiency of uridine diphosphate-glucose-hexose-1-phosphate uridylyltransferase, usually called galactose-1-phosphate uridylyltransferase or GALT) is a rare, inherited metabolic disease where the body cannot safely break down the sugar galactose, found mainly in lactose (milk sugar). When this enzyme is missing or very low, toxic substances such as galactose-1-phosphate and galactitol build up in the liver, brain, eyes and other organs, especially in newborn babies who are drinking breast milk or formula containing lactose. Without treatment, babies can quickly develop liver failure, infections and even death. [1]
This condition is usually inherited in an autosomal recessive way, which means a baby gets one faulty GALT gene from each parent. Parents are healthy “carriers” but each pregnancy has a 25% chance of having an affected child. Early signs in a newborn may include poor feeding, vomiting, jaundice (yellow skin and eyes), enlarged liver, low blood sugar, bleeding problems and serious infections like sepsis. Stopping lactose and galactose in the diet quickly can reverse many of the life-threatening early problems, so newborn screening is very important. [2]
The enzyme belongs to a family of enzymes called UDP-glucose:hexose-1-phosphate uridylyltransferases. It normally changes UDP-glucose and galactose-1-phosphate into UDP-galactose and glucose-1-phosphate. Without this reaction, galactose-1-phosphate, galactose, and galactitol collect in the body and damage organs.
Even with early diagnosis and strict diet, some long-term issues can still happen, such as learning difficulties, speech problems, movement problems, weak bones and primary ovarian insufficiency (early loss of ovary function) in many females. Doctors think these problems are due to the long-term effects of toxic galactose-related chemicals and possibly other pathways we do not fully understand yet. Regular follow-up with metabolic specialists, dietitians, endocrinologists and other professionals is needed throughout life to monitor and manage these complications. [3]
Other names
This enzyme deficiency and the disease it causes are known by several other names. These names are often used in medical books and lab reports and all point to the same main problem: lack of GALT enzyme activity.
Common other names include:
Classic galactosemia
Galactosemia type I
GALT deficiency
Galactose-1-phosphate uridyltransferase deficiency
Galactose-1-phosphate uridylyltransferase deficiency
UDP-glucose–hexose-1-phosphate uridylyltransferase deficiency
All of these names describe the same basic disorder: the body cannot safely handle the milk sugar galactose because this specific enzyme does not work normally.
Types
Doctors now know that there is not just one single form of this disease. Different types or variants depend on how much enzyme activity is left, what exact gene change is present, and how severe the symptoms are.
Main types (list view, explained):
Classic (severe) GALT deficiency
In this type, the enzyme activity is almost zero or less than about 1–3% of normal. Babies get very sick in the first days or weeks of life after starting milk feeds. Without fast treatment, classic disease can cause liver failure, severe infection, and death.Clinical variant galactosemia
In this type, some enzyme activity is still present, but it is much lower than normal. Symptoms may appear later or be a little milder than in classic disease, but children can still develop serious liver, brain, or eye problems if not treated.Duarte variant galactosemia
In this milder variant, enzyme activity is reduced but not as low as in classic disease. Many people with Duarte variant do not develop severe symptoms, and long-term problems are less common, but careful follow-up is still needed.Other rare GALT variants
There are many different changes (mutations) in the GALT gene. Some cause very low enzyme activity; others cause moderate or mild loss of function. Lab tests can group people into severe, variant, or milder types based on how much enzyme activity and how much galactose-1-phosphate is found in the blood.
Causes
For this disease, there is one main real cause: a genetic change in the GALT gene. Many of the “causes” listed below are ways of describing how and why this gene problem appears in families or what makes the condition show itself.
GALT gene mutation
The basic cause is a permanent change (mutation) in the GALT gene. This change makes the GALT enzyme folded in the wrong way or not produced at all, so it cannot do its job in galactose metabolism.Autosomal recessive inheritance
The disease appears only when a baby receives two changed copies of the GALT gene, one from each parent. If a child has only one changed copy, they are a carrier but usually healthy.Both parents are carriers
When both parents carry one changed GALT gene, each pregnancy has a 25% chance to produce an affected child, a 50% chance of a carrier child, and a 25% chance of a child with two normal genes.Common “classic” mutations
In some regions, certain GALT mutations are especially frequent and strongly reduce enzyme activity. These common mutations make it more likely that two carriers will meet and have an affected baby.Population or ethnic background
Classic galactosemia is seen in all ethnic groups but is reported more often in some populations, such as people of Irish origin, likely because certain mutations are more common in these groups.Family history of galactosemia
If an older child or relative has classic galactosemia or GALT deficiency, future babies in the same family have a higher risk because the parents may both be carriers.Consanguinity (parents related by blood)
When parents are blood relatives (for example, cousins), they are more likely to share the same rare gene mutation, so the chance of having a baby with autosomal recessive conditions like GALT deficiency increases.Newborn exposure to lactose and galactose
The enzyme problem is present from birth, but signs appear only after the baby drinks milk (breast or formula), which contains lactose and galactose. Feeding exposes the metabolic block and triggers symptoms.Lack of or delay in newborn screening
In places where newborn screening is not available or is delayed, babies may drink milk for longer before diagnosis, so the underlying genetic problem causes more damage and disease appears more severe.Blood transfusion before newborn screening
If a baby receives a blood transfusion before the screening test, the donor blood can contain normal GALT enzyme. This may hide the enzyme deficiency temporarily and delay the diagnosis.Compound heterozygosity
Many children have two different GALT mutations, one on each chromosome. Some pairs of mutations give almost no enzyme activity, while others allow a small amount, leading to different clinical types.Misfolding of the GALT enzyme
Some mutations make the enzyme unstable or easily broken down in cells. Even if it is made, it quickly falls apart, so there is not enough working enzyme to clear galactose-1-phosphate.Reduced transport or processing in cells
A damaged enzyme may not reach the right place in the cell or may not bind to its normal sugar partners, so the metabolic pathway for galactose remains blocked.High intake of galactose in early life
When the enzyme is absent, every feed that contains lactose and galactose adds more toxic sugar to the baby’s system. This does not cause the gene defect but makes the disease much more obvious and dangerous.Lack of early medical care
If early warning signs such as jaundice, vomiting, or poor feeding are not recognized as serious, the baby may continue normal milk feeding and the underlying GALT deficiency causes more organ damage.Limited genetic counseling
In families with a known child with galactosemia, not having genetic counseling means parents might not know their recurrence risk or options like prenatal or pre-implantation genetic testing.Incomplete follow-up of borderline newborn screens
Sometimes newborn screening results are borderline or unclear. If repeat testing is not done promptly, a true GALT deficiency can be missed or diagnosed late.Unrecognized milder variants
People with milder variants such as Duarte type may not be diagnosed in infancy. If they eat high-galactose diets and have some enzyme deficiency, they might develop subtle problems later.Coexisting liver stress
Other conditions that stress the liver (such as infections or other metabolic problems) can worsen the effects of GALT deficiency, though they do not cause the enzyme defect itself.Lack of awareness in healthcare systems
In low-resource areas where galactosemia is not well known, physicians may not think of GALT deficiency, so diagnosis is late and the genetic cause continues to be passed through families.
Symptoms
Symptoms usually start within days or weeks after birth, once the baby has taken milk. Without treatment, the condition can affect many systems: liver, brain, eyes, kidneys, and in females the ovaries.
Poor feeding and loss of appetite
Newborns may not want to feed, take very little milk, or stop sucking well. This happens because the build-up of toxic sugar makes them feel very ill and weak.Vomiting and diarrhea
Soon after starting milk, many babies vomit and may have loose stools. This is due to irritation of the gut and the overall sickness caused by the galactose build-up.Failure to gain weight (failure to thrive)
Even when feeding is tried often, the baby does not gain weight and may even lose weight. Toxic sugars and liver dysfunction mean food is not turned into healthy growth.Lethargy and weakness
Babies may be very sleepy, floppy, or difficult to wake. This is a sign that the brain and muscles are not getting normal energy and may be affected by high galactose-1-phosphate levels.Jaundice (yellow skin and eyes)
The skin and the white part of the eyes may become yellow because the liver is damaged and cannot process bilirubin correctly. This jaundice often gets worse instead of better.Enlarged liver (hepatomegaly)
The liver may grow big and firm, which a doctor can feel on exam. This happens because toxic sugars damage liver cells and cause swelling and scarring.Bleeding problems
Sick livers cannot make normal clotting factors, so babies may bruise easily or bleed more than expected. This can show as nosebleeds, bleeding from the cord stump, or bleeding in the gut.Low blood sugar (hypoglycemia)
Because the liver is not working well and metabolism is blocked, the baby can have low blood sugar. This can cause shakiness, sweating, or even seizures if very severe.Infections, especially E. coli sepsis
Many untreated babies develop severe blood infections, often with a bacteria called E. coli. The immune system does not work properly when nutrition and liver function are very poor.Cataracts (cloudy lenses in the eyes)
Galactose and galactitol collect in the lens of the eye and draw in water, making the lens cloudy. This can cause white or gray pupils and, if not treated, permanent visual problems.Swelling of the body (edema and ascites)
Liver failure can cause fluid to leak into tissues and the belly, leading to a swollen abdomen (ascites) and puffiness around the eyes or legs.Developmental delay
Even when diet treatment is started, some children have slower development in speech, learning, or movement because early brain injury may have already occurred.Movement problems (tremor or poor coordination)
Some older children and adults with GALT deficiency develop tremors, balance problems, or clumsy movements due to long-term effects on the brain and nerves.Speech and learning difficulties
Language problems, learning differences, and low school performance are more frequent in classic galactosemia, even with good dietary control, showing that the disease can affect brain development early.Premature ovarian insufficiency in females
Many girls and women with classic galactosemia develop early loss of ovarian function. They may have delayed puberty, irregular periods, or infertility because the ovaries are very sensitive to the metabolic defect.
Diagnostic tests
Diagnosis combines clinical signs, newborn screening, special blood tests, and sometimes genetic tests and imaging. Early diagnosis is vital so that milk can be stopped and a galactose-free diet started quickly.
Physical exam tests
General newborn physical exam
The doctor looks at the baby’s overall condition: alertness, color, breathing, and body tone. Signs such as lethargy, poor feeding, and weight loss make the doctor suspect a serious metabolic problem like GALT deficiency.Check for jaundice and liver enlargement
The doctor inspects the skin and eyes for yellow color and gently feels the abdomen to see if the liver is enlarged or tender. Persistent or worsening jaundice with a large liver is a strong clue to galactosemia.Assessment of hydration and swelling
The baby is checked for dry mouth, sunken eyes, decreased urine, or swelling of the belly and legs. Dehydration from vomiting and diarrhea, plus fluid build-up from liver failure, fits the picture of classic galactosemia.Neurologic examination
The doctor checks reflexes, muscle tone, and response to stimulation. Floppy tone, poor suck, or seizures in a sick, jaundiced newborn raise concern for metabolic diseases including GALT deficiency.
Manual (bedside) tests
Newborn heel-prick screening test
A few drops of blood are taken from the baby’s heel and dried on filter paper. Many newborn screening programs measure GALT enzyme activity and/or total galactose in this sample to detect classic galactosemia very early.Repeat dried blood spot GALT assay
If the first screen is abnormal, another heel-prick sample is collected. The repeat test confirms low GALT activity and helps rule out lab error or temporary problems.Bedside urine reducing substances test
A quick chemical strip can be used on urine to check for reducing sugars. A positive test suggests that sugars like galactose are spilling into the urine, which supports a diagnosis of galactosemia, though it is not specific.Simple eye exam with light (torch exam)
Using a bright light, the doctor looks at the red reflex in the pupils. A dull or white reflex may show early cataracts, which are common in untreated galactosemia.
Laboratory and pathological tests
Quantitative GALT enzyme activity in red blood cells
This is the key diagnostic test. A lab measures how much GALT enzyme activity is present in red blood cells. Very low or absent activity confirms classic GALT deficiency.Erythrocyte galactose-1-phosphate level
This test measures the amount of galactose-1-phosphate inside red blood cells. High levels show that galactose is not being processed properly and support the diagnosis and follow-up of treatment.Blood galactose or total galactose
Some labs directly measure galactose or total galactose (galactose plus galactose-1-phosphate) in plasma or dried blood spots. High total galactose together with low GALT activity strongly suggests classic galactosemia.Liver function tests (AST, ALT, bilirubin, albumin)
These tests show how well the liver cells are working. High liver enzymes and bilirubin plus low albumin in a sick newborn help show that liver damage is present, which fits the pattern seen in untreated GALT deficiency.Coagulation profile (PT, INR, aPTT)
These tests measure blood-clotting time. In galactosemia-related liver failure, clotting factors fall and clotting time becomes long, which alerts doctors to the risk of dangerous bleeding.Serum electrolytes and blood glucose
Glucose, sodium, potassium, bicarbonate, and other values are checked to look for low blood sugar, dehydration, and metabolic acidosis. These changes are common in newborns with severe galactosemia.Blood and urine cultures
Cultures are done to check for infection, especially E. coli sepsis, which is strongly linked to classic galactosemia. Finding this infection in a very jaundiced, vomiting newborn should trigger urgent metabolic testing.Genetic testing of the GALT gene
DNA testing looks for known mutations in the GALT gene. This test confirms the exact genetic cause, helps classify the type (classic, variant, Duarte), and is useful for family counseling and future pregnancies.
Electrodiagnostic tests
Electroencephalogram (EEG)
If a baby has seizures or abnormal movements, an EEG can record brain electrical activity. Abnormal patterns show that the brain is under stress, which in this setting is often due to metabolic toxicity and liver failure.Evoked potential or hearing tests
Auditory brainstem response or other evoked potentials may be used to check hearing and nerve pathways, especially later in childhood. These tests can detect subtle nerve or brain involvement from early metabolic injury.
Imaging tests
Abdominal ultrasound
Ultrasound uses sound waves to create images of the liver, gallbladder, and spleen. It can show an enlarged or damaged liver, extra fluid in the abdomen, and other signs of chronic liver disease in galactosemia.Ophthalmologic slit-lamp examination
An eye doctor uses a slit-lamp (a special microscope with bright light) to look closely at the lens. This test can detect early cataracts caused by galactitol build-up in the lens, even before vision is badly affected.
Non-pharmacological treatments (therapies and others)
Lifelong lactose- and galactose-restricted diet
The most important treatment is a lifelong diet that removes lactose and strongly limits galactose. In practice, this means avoiding regular cow’s milk, breast milk and most dairy products, because they all contain lactose, which breaks down into glucose and galactose. A special formula (soy-based or other lactose-free formula) is started as soon as the condition is suspected, often before the diagnosis is fully confirmed. This diet prevents the rapid build-up of harmful galactose-1-phosphate in the baby’s body and greatly reduces the risk of liver failure, sepsis and death. [1]Use of lactose-free infant formula and milk substitutes
Newborns and infants with GALT deficiency are fed lactose-free formulas, usually based on soy or special elemental formula. As children grow, they can drink plant-based milks that do not contain added lactose, while making sure they still get enough protein, calcium and other nutrients. This approach helps maintain normal growth and development while protecting the baby from the toxic effects of galactose. Parents are usually trained by a metabolic dietitian to choose safe products and to check labels carefully. [2]Dietetic counseling and regular nutrition review
Because the diet is strict and long-term, families need regular sessions with a specialist dietitian who understands inborn errors of metabolism. The dietitian helps balance safety (low galactose) with good nutrition (enough calories, protein, vitamins and minerals). Over time, small natural sources of galactose (like some fruits and vegetables) may be allowed, according to international guidelines and individual tolerance. Good dietetic support lowers the risk of growth failure, nutrient deficiency and poor quality of life. [3]Newborn screening and family cascade testing
In many regions, galactosemia is identified through newborn screening, which measures galactose levels or GALT enzyme activity from a heel-prick blood spot. If a baby screens positive, confirmatory tests are done quickly and the diet is changed immediately. Once a diagnosis is confirmed, carrier testing and prenatal options can be discussed for parents and relatives, helping families plan future pregnancies and detect affected babies early. [4]Written emergency (“sick-day”) plans
People with galactosemia can become very unwell during infections or surgery. A written emergency plan explains how to manage fluids, energy intake, and when to go to hospital if the person is vomiting, not eating, or has fever. Families keep this plan with them and share it with local doctors and emergency departments. Clear sick-day plans help prevent dehydration, low blood sugar and other metabolic complications. [5]Developmental and educational support
Some children with classic galactosemia develop speech and language delays, learning difficulties or motor coordination problems. Early assessment by a developmental pediatrician and ongoing support in school (extra time, special education services, classroom accommodations) can improve learning and social skills. Tailored educational plans help children reach their full potential even if they have mild cognitive challenges. [6]Speech and language therapy
A distinctive problem in galactosemia is developmental verbal dyspraxia, where the child knows what they want to say but has trouble planning and coordinating the movements of the mouth. Regular sessions with a speech and language therapist can greatly improve clarity of speech, vocabulary, and communication confidence. Early therapy, started in preschool years, usually gives the best results. [7]Physiotherapy and occupational therapy
Some people develop motor problems, balance issues or fine-motor difficulties (like writing or using buttons). Physiotherapists help with strength, coordination and balance exercises, while occupational therapists focus on everyday tasks such as writing, dressing, and using tools. These therapies can reduce falls, improve independence and support participation in school, sports and work. [8]Bone health monitoring and lifestyle measures
Because of dietary limits and possible hormone problems, people with galactosemia can have low bone mineral density. Regular checks of vitamin D, calcium intake and bone density scans are recommended. Non-drug measures such as weight-bearing exercise, safe sunlight exposure and a balanced diet rich in calcium and vitamin D (from non-dairy sources) support stronger bones alongside any medical treatment. [9]Psychological and mental-health support
Living with a chronic rare disease, plus dealing with learning or fertility problems, can cause anxiety, low mood or social stress. Access to psychologists or counselors familiar with chronic illness provides a safe space to talk about worries and build coping skills. Support groups and patient organizations also help families share experiences and practical tips. [10]Endocrine and fertility counseling for females
Many girls and women with classic galactosemia develop primary ovarian insufficiency (POI), meaning their ovaries stop working much earlier than usual. Endocrinologists and fertility specialists can monitor hormone levels, explain menstrual changes and discuss choices such as hormone replacement therapy, egg storage (if possible early in life), or other fertility options. Honest, age-appropriate counseling helps patients plan for relationships and family life. [11]Genetic counseling for the whole family
Genetic counselors explain how GALT deficiency is inherited, the chance of having another affected child, and testing options for relatives. They can also discuss prenatal or pre-implantation genetic testing for future pregnancies if families wish. This support helps people make informed, personal decisions about family planning. [12]
Drug treatments
Important: The medicines below are examples of how doctors may treat complications of galactosemia, not the enzyme defect itself. Doses must always be chosen by a qualified clinician for each individual.
Broad-spectrum intravenous antibiotics for sepsis
Newborns with undiagnosed galactosemia can develop life-threatening sepsis, often from E. coli. Doctors treat this urgently with intravenous (IV) broad-spectrum antibiotics, such as third-generation cephalosporins or other agents approved by the FDA for neonatal sepsis. These drugs are given in hospital, usually every 8–24 hours depending on the medicine and the baby’s weight and kidney function, to quickly clear the infection and reduce the risk of shock and death. [FDA-sepsis antibiotics]Vitamin D supplements (e.g., cholecalciferol)
Because dairy is restricted and bone health is at risk, many patients receive vitamin D3 (cholecalciferol) as an oral supplement. FDA-approved vitamin D preparations are used to help maintain normal blood vitamin D levels and support calcium absorption and bone mineralization. Doctors select the dose based on age, blood levels and guidelines; too much vitamin D can cause high calcium and kidney problems, so levels are checked regularly. [FDA vitamin D preparations]Calcium supplements
Calcium tablets or chewables are often prescribed to reach recommended daily intake without using regular dairy products. These supplements help build and maintain strong bones and teeth, especially in growing children and in adults with low bone mineral density. Doctors consider total dietary calcium, vitamin D status and bone density results to select a safe daily dose and to avoid kidney stones or high blood calcium. [Calcium products]Thyroid hormone replacement (levothyroxine)
Some individuals may develop hypothyroidism, and doctors can treat this with synthetic thyroid hormone such as levothyroxine, an FDA-approved drug used for replacement therapy in congenital or acquired hypothyroidism. [FDA levothyroxine label] Levothyroxine is usually taken once daily on an empty stomach; doses depend on body weight, age and thyroid blood tests. Over- or under-treatment can cause heart, bone or energy problems, so regular monitoring is essential. [4]Hormone replacement therapy for ovarian insufficiency
Girls and women with POI may receive estrogen-progestin hormone replacement, often using combined oral contraceptive pills or other hormone preparations that are FDA-approved for contraception and hormone therapy. [FDA norethindrone/ethinyl estradiol labels] These medicines are usually taken daily to provide estrogen for bone and cardiovascular health and progestin to protect the uterus. Side effects can include nausea, headache, mood changes and a small increased risk of blood clots, so doctors carefully assess benefits and risks. [5]Bisphosphonates for severe low bone density (selected cases)
In older teens or adults with significantly low bone mineral density and fractures, specialists may consider bisphosphonates (e.g., alendronate), which are FDA-approved for osteoporosis. These drugs slow down bone breakdown and can increase bone density over time. They are usually given weekly or monthly in carefully chosen doses, with instructions to stay upright and drink water after taking oral forms to limit stomach irritation. Use is individualized because long-term safety in rare metabolic diseases is still being studied. [6]Psychiatric medications when needed (e.g., SSRIs)
Some people with galactosemia experience anxiety, depression or other mental-health conditions. When psychotherapy alone is not enough, doctors may prescribe antidepressants such as selective serotonin reuptake inhibitors (SSRIs), which are FDA-approved for depression and anxiety disorders. Doses start low and are adjusted gradually while monitoring for side effects like nausea, sleep changes or mood swings. Medication choice is always personalized and combined with counseling. [7]Supportive medications during acute liver dysfunction
In the newborn period, before diet treatment takes full effect, babies may need medicines to manage liver failure complications such as vitamin K for bleeding, lactulose for high ammonia, or specific treatments for low blood sugar and electrolyte imbalance. These medicines are standard FDA-approved therapies for these complications and are used alongside strict galactose restriction in an intensive care setting. [8]
(In real clinical practice, there is no specific drug that “fixes” the GALT enzyme, so drug treatment is focused on treating complications and supporting organs, as recommended in international guidelines.) [9]
Dietary molecular supplements
Calcium (again, as a dietary supplement)
Calcium supplements are considered a dietary molecular supplement because they provide the mineral in purified form, separate from lactose-containing dairy foods. Adequate calcium helps support bone mineralization and normal muscle and nerve function. Doctors adjust the dose based on age, diet and blood tests, and they ensure that the product is lactose-free or safe for people with galactosemia. [1]Vitamin D3 (cholecalciferol)
Vitamin D3 is a fat-soluble vitamin that helps the gut absorb calcium and supports normal bone and immune function. In galactosemia, limited dairy intake and possible reduced sun exposure can lead to low levels, so supplementing vitamin D3 is often recommended. The dose is chosen according to age and blood levels; both deficiency and excess can be harmful, so monitoring is important. [2]Vitamin K (for bleeding risk in liver dysfunction)
Some infants with severe liver involvement have low vitamin K–dependent clotting factors, increasing the risk of bleeding. Vitamin K can be given as a supplement or injection to help the liver produce these clotting factors until the diet and liver function improve. This support reduces the risk of dangerous bleeding in the brain or gut. [3]Folic acid and B-vitamin complexes
B-vitamins, including folic acid, are important for red blood cell formation and many enzyme reactions. In people with dietary restrictions or poor intake, doctors may recommend a B-complex supplement to support normal blood health and energy metabolism. These supplements must be checked to ensure they do not contain lactose or galactose as fillers. [4]Docosahexaenoic acid (DHA) and omega-3 fatty acids
Omega-3 fatty acids, especially DHA, play roles in brain and eye development. Some clinicians consider DHA supplements in children with developmental or learning difficulties, although strong evidence in galactosemia is limited. If used, a lactose-free preparation is chosen, and the dose is tailored to age and nutritional needs. [5]Probiotics (carefully selected)
Probiotics are “good bacteria” that may support gut health. Some preparations help prevent antibiotic-associated diarrhea or may improve general digestive comfort. In galactosemia, any probiotic must be carefully checked to ensure it does not contain lactose or galacto-oligosaccharides that could add galactose load. Evidence is still emerging, so use is individualized. [6]
Regenerative and immune-supportive experimental approaches
At the moment, no regenerative, stem-cell or gene-therapy drugs are FDA-approved specifically for GALT deficiency. Research is exploring possibilities such as gene therapy, where a working copy of the GALT gene is delivered to cells using viral vectors, and pharmacological chaperones, which are small molecules that help misfolded enzymes work better. These ideas are currently being studied in cells and animal models and sometimes in early-phase human research, but they are not standard care and should only be used in clinical trials under expert supervision. [1]
Because the immune system can be stressed by repeated infections and chronic disease, doctors may also focus on general immune support: keeping vaccinations up to date (including pneumococcal and influenza vaccines), ensuring good nutrition and vitamin D status, and treating infections promptly. These strategies use existing approved vaccines and medicines, not special “immune booster” drugs, and they are part of standard preventive medicine for all patients with chronic conditions. [2]
Surgeries and procedures
Liver transplantation
In rare, extremely severe cases where liver failure does not improve even with strict galactose restriction and full medical support, liver transplantation may be considered. This surgery replaces the diseased liver with a healthy donor liver. It can correct liver failure but does not fully cure galactosemia, because GALT is needed in many tissues, so dietary care and monitoring still continue. Decisions about transplant are complex and made by multidisciplinary teams in transplant centers. [1]Cataract surgery
If galactose restriction is delayed, babies may develop cataracts due to galactitol build-up in the lens of the eye. Some cataracts improve once the diet changes, but if lens clouding is severe and does not resolve, eye surgeons may perform cataract extraction. This procedure removes the cloudy lens and usually places an artificial lens, improving vision and reducing the risk of amblyopia (lazy eye). [2]Orthopedic procedures for fractures or bone deformities
People with severe osteoporosis may suffer fractures or deformities in the spine or long bones. In such cases, orthopedic surgery may be needed to stabilize fractures, correct deformity or relieve nerve compression. This is combined with medical treatment of bone weakness and rehabilitation to restore mobility. [3]Gynecologic procedures related to ovarian insufficiency
Women with POI may sometimes need gynecologic procedures, such as hysteroscopy or laparoscopy, to investigate unusual bleeding or pelvic pain, but surgery is not a routine treatment for ovarian failure itself. Management usually focuses on hormone therapy rather than operations, unless there is a separate gynecologic problem. [4]
Prevention and lifestyle
Because galactosemia is inherited, we cannot prevent the gene change, but we can prevent many health problems by:
Newborn screening and early diet change so galactose is removed before serious liver damage or sepsis. [1]
Strict lifelong avoidance of high-galactose foods, especially milk and most dairy products. [2]
Regular specialist follow-up to find and treat complications early (speech, learning, bone health, hormones). [3]
Vaccinations and prompt infection care to reduce risk of severe illness. [4]
Healthy lifestyle habits (exercise, sleep, mental-health care) that support overall resilience. [5]
When to see doctors
People with GALT deficiency should contact a doctor or go to emergency care immediately if they notice:
In babies: poor feeding, vomiting, jaundice, floppy body, fever or being unusually sleepy or hard to wake. [1]
In children or adults: high fever, severe abdominal pain, confusion, breathing trouble, or signs of infection like painful urination or chest pain when breathing. [2]
Signs of liver problems: yellow eyes, dark urine, pale stools, easy bruising or swelling of the belly. [3]
In females: missed or very irregular periods, hot flashes or difficulty getting pregnant, which may suggest ovarian insufficiency and need endocrine review. [4]
Regular planned visits with the metabolic team, dietitian, endocrinologist and other specialists are also important even when the person feels well.
What to eat and what to avoid
Generally safer to eat (if confirmed by your metabolic team):
Lactose-free or soy-based milks and yogurts specifically labeled safe for galactosemia.
Fresh fruits and vegetables in usual portions (some guidelines allow them because they contain only tiny amounts of galactose).
Grains (rice, wheat, oats), breads and cereals that do not contain lactose or milk powder.
Meat, fish, eggs and plant proteins like lentils and beans, which provide protein without significant galactose.
Plant oils, nuts and seeds (if tolerated), which give healthy fats and energy. [1]
Generally best to avoid (unless your specialist says otherwise):
Cow’s milk, goat’s milk, breast milk and standard infant formulas containing lactose.
Cheese, ice-cream, cream, yogurt and other obvious dairy products.
Foods with ingredients such as “milk solids”, “whey”, “casein”, “lactose” or “milk powder”.
Some processed foods (desserts, chocolates, sauces) that may hide lactose or galactose in additives.
Any supplement or medicine that uses lactose as a filler, unless the metabolic team has confirmed it is safe in the dose used. [2]
Because recommendations can change as new evidence appears, families should always follow the latest written diet plan from their own metabolic center.
Frequently asked questions (FAQs)
Is galactosemia the same as lactose intolerance?
No. Lactose intolerance is usually due to low levels of lactase in the gut and mainly causes stomach upset, gas and diarrhea. Classic galactosemia is much more serious; it is a genetic enzyme deficiency inside the body’s cells that can cause liver failure, infections and long-term complications if galactose is not restricted from birth. [1]If treatment starts early, is my child “cured”?
Early diagnosis and prompt lactose/galactose restriction greatly improve survival and prevent many severe early problems, but they do not completely cure the condition. Even well-treated individuals may develop speech, learning, movement or hormonal issues, so lifelong monitoring is needed. [2]Can adults with galactosemia ever relax the diet?
Some guidelines allow a small amount of natural galactose from non-dairy foods in older children and adults, but high-galactose foods (milk and most dairy) must still be avoided. The exact level of restriction should follow written advice from the specialist team, because evidence about long-term tolerance is still developing. [3]Will my child have normal intelligence?
Outcomes vary. Many children attend regular school, but some have learning difficulties or need extra support, especially in speech and language. Early therapy and school accommodations can make a big difference in everyday functioning and quality of life. [4]What about sports and physical activity?
Most people with galactosemia can safely join in normal activities and sports, which are actually helpful for bone and mental health. The main limitations are dietary, not physical. Any special risks (such as very low bone density or heart problems) should be discussed individually with the doctor. [5]Can females with galactosemia have children?
Many females develop primary ovarian insufficiency, but some still have spontaneous puberty and even pregnancies. Fertility options may include early counseling, hormone therapy and assisted reproductive techniques. Because choices are complex and personal, care from an experienced endocrinologist and fertility team is essential. [6]Is gene therapy available now?
No approved gene therapy exists yet for classic galactosemia. Research in cells and animal models is promising, but human treatments are still experimental. Anyone interested in trials should only join studies run by recognized metabolic centers or academic hospitals. [7]Can I breastfeed a baby with galactosemia?
Breast milk contains lactose and therefore galactose, so breastfeeding is not safe for babies with classic galactosemia once the diagnosis is confirmed. Before diagnosis is known, a baby may receive breast milk; after diagnosis, milk is switched to lactose-free formula under medical supervision. [8]How often are check-ups needed?
In infancy, visits are frequent—often every few weeks or months. Later, most clinics see children and adults at least once a year, with extra visits if problems arise. At these visits, doctors check growth, lab tests (like galactose-1-phosphate), bone health, hormones and school progress. [9]Can my child have vaccines on the usual schedule?
Yes. Standard vaccinations, including live vaccines, are recommended for most patients unless there is another medical reason not to receive them. Vaccines help prevent infections that could be especially dangerous for people with chronic liver or metabolic conditions. [10]Do carrier parents have any health problems?
Carriers usually have one normal and one faulty GALT gene and do not have classic galactosemia. They generally live healthy lives but have a risk of having affected children if their partner is also a carrier. Genetic counseling can explain these risks and testing options. [11]Is it safe to use medicines that contain lactose?
Some medicines use lactose as a filler. In many metabolic clinics, tiny amounts of lactose from medications may be allowed because the total galactose exposure is very small, but practices differ. Always show new medicines to the metabolic team so they can decide whether they are acceptable or suggest an alternative. [12]Can siblings be tested even if they seem healthy?
Yes, and this is strongly recommended. Because classic galactosemia can be life-threatening in early infancy, siblings (especially newborns) should be tested for GALT activity or genetic changes as soon as there is suspicion in the family, even if they look well. [13]Does galactosemia affect life expectancy?
With modern newborn screening, strict diet and good medical care, many people with classic galactosemia live into adulthood. However, they may face health challenges like bone problems and ovarian insufficiency. Ongoing research is trying to improve long-term outcomes and quality of life. [14]Where can families find reliable information and support?
Reliable information comes from metabolic clinics, national rare disease organizations and professional guidelines, such as the international clinical guideline for classical galactosemia. Patient groups and online communities, when moderated by reputable organizations, can provide emotional support and practical tips for daily life. [15]
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.
