Galactosemia

Galactosemia is a genetic condition and there is no cure. A person will never outgrow the disorder. People with galactosemia must remain on diet that excludes milk and dairy products for life.

Some people with galactosemia may choose to stop following their diet as they get older. This is called poor compliance. The modified diet for galactosemia can be restrictive to some people and they may have trouble staying on the diet. The diet is less restrictive outside of infancy and childhood, but people must avoid milk and dairy products for life. Children, particularly older children, may stop following the diet because they are embarrassed or their classmates may make unkind comments. Children or teenagers who struggle with compliance should talk to their parents, physicians and a psychologist to work through these issues.

Sometimes people stop following the diet because it’s working well and they feel better. They may start to think that they do not need to follow the diet anymore or ‘cheat’ on the diet more and more often. However, the less they follow their diets, the more galactose will keep building up in their bodies. Galactosemia can cause problems before people realize it, and although they feel well overall, it can affect their school or work performance, social interactions and other aspects of life. The special diet to treat galactosemia must be followed for life. Even if someone feels better and their symptoms improve, they need to continue to follow their treatment plan as developed by their physician and medical team in order to continue feeling better.

In a family with galactosemia, tests can be done to see whether other family members are carriers for the disorder. (Carriers do not have symptoms and have one working and one non-working copy of the GALT gene.) However, the specific gene changes in that family needs to be known. If known, all siblings and other at-risk relatives can be tested. Molecular genetic testing, which are tests that look for changes to genes, can be performed. A newborn child in a family with a history of galactosemia should be tested through molecular genetic testing. A genetic counselor or a physician with experience in galactosemia can provide advice about how a confirmed diagnosis can affect other family members. Medical geneticists can be found through the American College of Medical Genetics and a genetic counselor can be found through the National Society of Genetic Counselors.

Support groups can put you in contact with other people or families that have galactosemia. Support groups include Galactosemia Foundation, Galactosaemia Support Group (UK), the European Galactosemia Society, and the Australian Galactosaemia Support Network.

There are also online communities for rare disorders such as RareConnect, RareShare, or Inspire, which allow individuals and parents to share experiences and advice about dealing with rare disorders.

All 50 states in the U.S. screen for galactosemia at birth. Galactosemia is one of the few disorders that it is mandatory for all states to screen for.

Galactosemia is a rare genetic disorder. People with this disorder are missing an enzyme called galactose-1-phosphate uridyl transferase or Gal-1-PUT. This enzyme has a job. It is supposed to break down galactose in the body. Galactose is a sugar. The body gets most of its galactose from the breakdown of lactose, which is the main sugar in milk. Galactose is supposed to be broken down further into another sugar called glucose (which is a main energy source for the body) and other molecules essential for the proper function of the body. Because people with galactosemia are missing an enzyme, galactose cannot be broken down and instead ends up building up in the body. When galactose builds up, it becomes toxic to the cells. The name, galactosemia, means ‘too much galactose in the blood.’ If not identified and treated promptly, life-threatening complications can occur. Most infants with galactosemia are diagnosed through newborn screening and put on a lactose-restricted diet within the first 10 days of life. Despite early recognition and prompt treatment, infants and children with galactosemia remain at risk for delays in reaching developmental milestones, speech delays, or problems with motor function. Changes (mutations) to the GALT gene cause classic galactosemia.

In addition to classic galactosemia, some individuals have clinical variant galactosemia. It is caused by different mutations to the GALT gene and has the same signs and symptoms as classic galactosemia. Another form of galactosemia is called Duarte variant galactosemia. The Duarte form has not been shown to cause any signs or symptoms, and many doctors do not consider it a real disease. However, adequate studies to confirm this have not been done and there have been anecdotal reports of mild symptoms in some people.

Galactosemia is caused by gene changes in the GALT gene. People have about 20,000-25,000 genes in their bodies. Our genes contain our body’s genetic information, called DNA; genes are segments of DNA found on chromosomes. Genes are inherited from our parents and passed on to our children. Genes are like our body’s instruction manual – they control the growth, development and normal function of the body. Genes produce specific proteins that the body needs to grow and work properly. When there is an unexpected change in a gene, the protein that the gene produces may be absent or not work properly.

To find a medical professional nearby who can discuss information about gene changes in the GALT gene and galactosemia, a listing of medical geneticists can be found at the American College of Medical Geneticists website and genetic counselors can be found on the National Society of Genetic Counselors website.

Galactosemia is caused by a change (variant) in the GALT gene. Not all changes in a gene necessarily cause disease. If a change is known to cause galactosemia, it is known as a pathogenic or disease-causing variant. Specific changes in the GALT gene can cause classic galactosemia, clinical variant galactosemia or Duarte variant galactosemia. However, sometimes gene changes are found and scientists are unsure what it means, either because it has not been found before or has only been found in a few people. This is known as a variant of unknown significance. If you have a variant of unknown significance in the GALT gene, talk to your doctor about further testing that may help find out whether the gene change is pathogenic or not. A genetic counselor may also be able to help you review your test results. To find a genetic counselor near you who can discuss testing and results, visit the National Society of Genetic Counselors Find a Genetic Counselor website.

If your baby receives a positive result for galactosemia from newborn screening, it does not mean that your child definitely has the disorder. Newborn screening can cause "false positives". Further testing is needed to know for sure whether a child has galactosemia. Parents will be contacted by your infant’s doctor or your state’s newborn screening program to schedule additional testing. Your baby will be put on a lactose-free until the diagnosis is confirmed.

Rare diseases that affect multiple organ systems like galactosemia can benefit from a multidisciplinary approach. This approach involves healthcare professionals with specialized skills and expertise. They work together to make treatment recommendations and to provide quality care of individuals and families. Depending upon the specific symptoms in an individual multidisciplinary team may require a specialist for liver disorders (hepatologist) who will monitor liver function and health; a specialist for the brain and central nervous system (neurologist) who will monitor the health and function of the brain and nerves; a specialist for the eyes (ophthalmologist) that will monitor eye health and function; a specialist in the hormonal system (endocrinologist); a nutritionist who can develop a special diet; a specialist in digestive disorders (gastroenterologist); a genetic counselor who can help people understand the disease and the implications for the person and other family members; and a metabolic disease specialist.

Talk to your doctor about the best specialists in your area to follow an individual with galactosemia.

Infants with galactosemia appear normal at birth. Since galactosemia is often diagnosed through newborn screening, treatment is usually begun before symptoms develop. With prompt diagnosis and treatment, the severe complications of galactosemia can be avoided.

If infants are not treated, they will develop signs and symptoms including irritability, feeding difficulties, diarrhea, and vomiting. Infants may refuse to eat and be lethargic. Jaundice, a condition in which bilirubin (a yellow-orange pigment that is a normal product of the breakdown or red blood cells) builds up in the body, can develop. Jaundice is characterized by yellowing of the skin, eyes and mucous membranes of the body. Infants may fail to grow and gain weight, a condition called failure to thrive. Some infants will have liver and kidney damage. They are at risk of developing bacterial infections. Severe, widespread infection called sepsis is possible. Sepsis is usually caused by E. Coli infection. Some infants will have a milder form of the disorder and develop very few symptoms and no severe symptoms.

Many of these early signs and symptoms, particularly the more serious ones, can be avoided by prompt diagnosis and early treatment with a galactose-free diet. However, many infants and children remain at risk of developing complications despite treatment. This includes delays in reaching developmental milestones, cataracts, poor growth, problems with speech, learning disabilities, behavioral problems, and mild intellectual disability. Most girls with galactosemia develop primary ovarian insufficiency or failure. This is the loss of function of the ovaries before the age of 40. Young women may not experience normal menstruation and reproductive problems including infertility often occur. Adolescents and adults may have neurological symptoms including tremors, a loss of control of muscles during voluntary movements (ataxia), and an impaired ability to control voluntary actions (dysmetria). Both men and women with galactosemia are at risk of developing osteoporosis, a condition that causes thinning of the bones and predisposes people to fractures.

These symptoms are characteristic of classic galactosemia and clinical variant galactosemia. People may not develop all of these symptoms. The severity of the disorder is highly variable. This means it can be very different in one person when compared to another. Some physicians believe that Duarte variant of galactosemia is a mild variant where symptoms rarely occur, while other physicians believe that it is only a biochemical finding, which is not associated with any symptoms and is not a real disorder.

To find a medical professional nearby who can discuss information about galactosemia, a listing of medical geneticists can be found at the American College of Medical Geneticists website and genetic counselors can be found on the National Society of Genetic Counselors website.

After a diagnosis of galactosemia is confirmed, families should seek a medical consultation with a physician such as a metabolic genetic specialist with experience in treating the disorder. Treatment with special diet that excludes milk and other dairy products should begin immediately upon the suspicion of galactosemia. People diagnosed with galactosemia will go through a series of tests to see how far along the disease is. These tests will tell a physician what parts of the body are affected and to what extent and can include neurological or eye (ophthalmologic) tests. Other initial steps will depend on how the disorder is affecting a person. Families should see a genetic counselor to help understand the genetic aspects of this disorder.

Other words can mean that a product or food has lactose in it. Lactose is broken down by the body into glucose and galactose. People with galactosemia cannot break down galactose, which builds up and becomes harmful. People with galactosemia should not include such food products with lactose in their diets. Other words that indicate lactose in food products include:

There is newborn testing for galactosemia. Newborns are tested for galactosemia as a part of the newborn screening program in every state of the United States. During routine newborn screening, a tiny sample of blood is taken from the heel of a newborn. This test, called a heel prick, involves getting a few drops of blood from a pinprick in the newborn’s heel. The blood is run through a machine that can detect the total content of galactose-1-phosphate in red blood cells and galactose in the blood. Addition testing on the sample can be done to detect the activity level of the GALT enzyme. Most infants galactosemia are detected shortly after birth through routine newborn screening. Some infants with classic variant galactosemia can be missed if the activity level of the GALT enzyme is not tested.

As of November 2016, there are several different studies for galactosemia listed on ClinicalTrials.gov, a government website that provides regularly updated information about federally and privately supported clinical trials. This is not a complete list of current research. Current studies are looking at pregnancy chances of women with galactosemia, the intervention and outcomes of Duarte variant galactosemia, and the success of universal newborn screening for metabolic disorders.

Most infants with galactosemia are diagnosed through routine newborn screening or NBS. NBS can detect elevated levels of galactose in the blood. NBS for galactosemia is offered for every state in the U.S. Further testing of a blood sample, called an enzyme assay, can detect reduced activity of the GALT enzyme and confirm a diagnosis. Physicians may conduct molecular genetic testing on infants with galactosemia. Physicians recommend these tests to help create the most effective treatment plan or allow other family members to have genetic testing done. These tests involve studying the GALT gene for changes (mutations) that cause the disorder. This can include targeted mutation analysis, where specific, known changes in a gene are looked for; sequence analysis, where a part or sequence of DNA within a gene is examined; or deletion/duplication analysis, where missing or extra regions of DNA are looked for within a specific gene. Molecular genetic testing must be done at specialized laboratories.

Galactosemia is treated with a special diet and the use of special medical food or formulas that do not contain milk and dairy products. People with galactosemia lack the enzyme galactose-1-phosphate uridyl transferase or Gal-1-PUT or GALT. Enzymes are substances that help reactions occur in the body. This specific enzyme is required to break down galactose in the body. In people with galactosemia, galactose and galactose byproducts build up in cells and become harmful to the body.

Some patients with galactosemia have virtually no enzyme activity, while others have a little bit of enzyme activity. So, the amount of galactose in the diet that people with galactosemia can tolerate is different in one person compared to another. Infants should receive soy-based formulas or elemental (hypoallergic) formulas. Some medical sources suggest lactose-free formula, but other medical sources state that these formulas have not been conclusively shown to be safe for infants and children with galactosemia. There is some debate among physicians about how strict the diet should be for people with galactosemia after childhood.

People with galactosemia should be seen by a dietician who has experience in treating metabolic disorders like galactosemia.

Carriers of an altered GALT gene that causes galactosemia do not develop symptoms of the disorder. They are at risk of passing the disorder on to their children if their partner is also a carrier. A genetic counselor in your area can help you understand more about your risk and the testing options for carriers.

The cost of special medical food for galactosemia can be different for one person or family when compared to another. There are many factors to consider. The supplier, the specific formula and medical foods, whether a person has insurance, whether the insurance plan will cover special medical foods, how much phenylalanine a person can handle in their diet, and other factors. For this reason, it is difficult to give an approximation about how much the use of medical food product would cost any given person. The cost is much more than it would be feed someone without galactosemia, and can be very expensive for an average family.

In the last few sessions of Congress, a bill has been introduced call the Medical Foods Equity Act. It has not been passed. This bill would require all federal programs to cover the cost of medical foods (formula and foods modified to be low in protein) for children and adults with galactosemia and similar disorders that require a special diet and supplemental medical foods.

Contact galactosemia support groups to learn about how much the diet and supplemental medical foods may cost your family. These groups may also have advice for dealing with insurance companies and the best places to find these products. Galactosemia support groups include the Galactosemia Foundation and the Galactosaemia Support Group.

Most infants with galactosemia in the United States are diagnosed through newborn screening. This allows treatment to begin immediately. If untreated, classic galactosemia will eventually lead to severe complications and death in the newborn period. However, treatment with a modified diet will prevent these severe complications. Despite treatment, affected infants and children remain at risk for delays in reaching developmental milestones and speech problems. Adults with classic galactosemia remain at risk for osteoporosis a condition that causes thinning of the bones that predisposes people to fractures. However, these issues are manageable and individuals with classic galactosemia can enjoy healthy lives with a normal lifespan.

We each get two copies of most of our genes from our parents. One copy comes from our mother and the other copy comes from our father. In galactosemia, both parents must pass along a nonworking copy of the GALT gene. Because of this, galactosemia is inherited in what is called an autosomal recessive pattern. People who have one working and one nonworking copy of the GALT gene are called carriers. When both parents are carriers, for each individual pregnancy, there is a 25% chance that both parents will pass along a nonworking copy of the gene and the child will have the disorder. There is a 50% chance that one parent will pass on the gene change and the other will not, meaning the child will be a carrier for the disorder. Finally, there is a 25% chance that both parents will pass along a working copy of the gene and the child will not have the disorder and will not be a carrier. If you are interested in finding out if you are a carrier for galactosemia, talk to your doctor about testing or contact a genetic counselor in your area.

Galactosemia is inherited in an autosomal recessive manner. This is one way a disorder or trait can be passed down through a family. Everyone has two copies of the GALT gene; one received from their father and one from their mother. Autosomal recessive inheritance means that a person receives a nonworking copy of the GALT gene from both parents. The parents have one working copy of the gene and one nonworking copy; they are carriers for galactosemia. Carriers do not develop symptoms of the disorder. If two people who are carriers have galactosemia, there is a 25% chance with each pregnancy that the child will have galactosemia and a 50% chance the child will also be a carrier for the disorder. If you have a family member with galactosemia and you would like to know if you are a carrier, talk to your doctor or meet with a genetic counselor to discuss testing options.

Galactosemia is caused by a change in a gene called GALT. The GALT gene produces an enzyme known as galactose-1-phosphate uridyl transferase or Gal-1-PUT, which is required to break down (metabolize) galactose in the body. Gene changes (mutations) in the GALT gene lead to deficient levels of this enzyme or ineffective versions of this enzyme. Since people with galactose lack functional levels or copies of this enzyme, they cannot break down galactose in the body. As a result, galactose (specifically derivatives of galactose called galactose-1-phosphate and galactitol) build up in the blood and tissues of the body. When enough of these substances build up they become toxic to the body.

Support groups have information about supporting research into galactosemia and most accept donations toward research. Some groups focus specifically on supporting research and some award research grants to promising areas of research. To donate money that could go to help research for these conditions, you can donate to the U.S.-based Galactosemia Foundation or the U.K.-based Galactosaemia Support Group.

To learn about ongoing clinical research into galactosemia ask a physician who specializes in the disorder. Genetic counselors and medical geneticists are also excellence sources of information about ongoing clinical trials and can offer advice about the pros and cons about participating in such a trial.

Ongoing studies for galactosemia can also be found on clinicaltrials.gov, a service of the U.S. National Institutes of Health. In Europe, the EU Clinical Trial Register performs a similar service.

Support groups also have information about ongoing clinical trials as well as information and advice about participating in clinical trials. Support groups for galactosemia include the Galactosemia Foundation and the Galactosaemia Support Group.

There are medical clinics around the U.S. and genetic clinics that can help people with metabolic disorders like galactosemia. The Galactosemia Foundation may be able to help you find a clinic or physician treating galactosemia near you. To find a genetics clinic near you, visit the Clinic Services Search Engine at American College of Medical Genetics and Genomics.

Some people with galactosemia find it challenging when it’s time to move (transition) from pediatric to adult care services. One big change is leaving a doctor with whom you have a long-standing relationship, a doctor who is familiar with both your condition and yourself. It can feel like ‘starting over’ as you’ll begin to work with new doctors and a new medical team. Another challenge in moving to adult care is that young adults must take greater responsibility for their health. They must manage their disorder, their diets, and any medications. They must bear greater responsibility for decisions concerning their health. Some hospitals have programs to help children with chronic disease transition to adult care services. Galactosemia support groups may also provide information or support on how to move from pediatric care to adult care services and what to expect. Talk to your child’s doctor about how and when to take steps to begin transition to adult care.

Children with galactosemia can attend and excel at school. Some children may develop delays in reaching certain milestones and speech problems, which can make school more challenging. Some children struggle in school, particularly in reading and math. These children may need special accommodations in school. They are eligible for an individual education plan (IEP) or a 504 plan. An IEP is a document that helps to guide the education of a child with a disability or special needs and ensures that they have access to the same educational opportunities as all children. The plan is individualized for each student.

A 504 plan ensures that students with disabilities can fully participate in school and have access to the same educational opportunities as all children. This plan is important for making sure a student with galactosemia can maintain their diet while fully participating in school with the same access to educational opportunities as all children.

Parents are encouraged to provide a school with a packet of information on galactosemia and to work with school officials including teachers, nurses, psychologists, the principal, and other professionals.

The U.S. Department of Education has information on individual education plans and on 504 plans.

The prevalence of classic galactosemia is estimated to be 1 in 48,000 people in the general population. This figure is based on newborn screening programs. Prevalence is the number of people who have a specific disorder within a specific population at a given time. Depending on the diagnostic criteria used, some estimates place the prevalence of classic galactosemia at 1 in 10,000 people. The clinical variant form is estimated to affect 1 in 20,000 people.

Individuals with galactosemia should be seen by doctors from multiple medical disciplines including a pediatrician and other physicians, nutritionists, dieticians, genetic counselors, social workers, nurses, and psychologists. Your pediatrician may need to contact a pediatric metabolic specialist. You can provide your doctor or pediatrician with education materials such as the information found at GeneReviews or UpToDate, Inc., which has information on clinical features and diagnosis as well as management and outcome.

Support groups can also provide physician education materials that you can share with your doctor. Support groups for galactosemia include the Galactosemia Foundation and the Galactosaemia Support Group.

Infants and young children with galactosemia must be on a more restrictive diet than older children and adults. There is no agreed upon diet for older children or adults with galactosemia. Talk to your physician and entire medical team, including a nutritionist and dietician, about the appropriate diet for yourself or your child.

Because most people with galactosemia have two genetic changes in their GALT genes in all of the cells of their body, they would have the same genetic testing results on blood, saliva, or other body tissue from a biopsy. However, most genetic tests for galactosemia are done on the blood.

Puberty can be delayed in girls who have galactosemia. Girls with this disorder may need to see an endocrinologist, a doctor who specializes in diagnosing and treating people with hormonal disorders. Galactosemia can also cause primary ovarian failure, which is when a woman’s ovaries stop working before the age of 40.

Most infants with galactosemia in the United States are diagnosed through newborn screening. This allows treatment to begin immediately. If untreated, classic galactosemia will eventually lead to profound intellectual disability, but this can be avoided if treatment is begun promptly. Infants with classic galactosemia (despite treatment) remain at risk for delays in reaching developmental milestones, problems with speech and learning disabilities. Some children struggle in school particularly with reading and math. Some children have average or above average intelligence.

Galactosemia causes infertility in some women. Doctors are not sure if galactosemia can affect fertility in men.

Women with galactosemia may experience a delay in reaching puberty and may fail to develop their period, a condition called (amenorrhea), or have irregular periods. Many women will have premature ovarian failure (POF). This condition is when a woman’s ovaries (eggs) stop working before she is 40 years old. This means the ovaries are not releasing hormones like estrogen that women need. POF is not early menopause, Women may still get their periods, but they may be irregular. Some women will be infertile. Some women may become pregnant despite having POF.

Doctors are not sure whether males with galactosemia have any reproductions issues. There are reports of men with galactosemia fathering child in the medical literature. But male reproductive issues have not been well studied for galactosemia.

People with galactosemia need to speak with their physician and entire medical team about the ability to have children. Women may need to see an endocrinologist, a doctor who specializes in diagnosing and treating people with hormonal disorders.

Many doctors believe that the Duarte variant of galactosemia does not cause symptoms regardless of whether a person is on restricted diet or not. Most people do very well and do not develop symptoms. However, there are anecdotal reports of infants or children having symptoms. Adequate studies have not been done to confirm whether the Duarte variant causes symptoms. Talk to your physician about what is appropriate for individuals with this variant form of galactosemia.

There is no agreed upon diet for people with galactosemia. Different clinics and doctors may recommend different diets or foods that contain a small amount of galactose. The recommended diet for people with galactosemia may also vary from one country to another. All people with galactosemia need to avoid milk and most dairy products including cow’s milk, yogurt, butter, many cheeses, and ice cream. There are some vegetables and fruits that contain free galactose including tomatoes, fruits, bananas, and apples. Most of these contain only small amounts of galactose. Some recommendations restrict these fruits and vegetables during infancy, but once a child is older they may be allowed. Galactosemia support groups can help parents understand dietary changes required for people with galactosemia. Parents should also work closely with their doctor, nutritionist and entire medical team to develop a diet that works best for their children.

Women who have an infant with galactosemia cannot breastfeed. Breast milk contains lactose, which is broken into glucose and galactose. Infants with galactosemia have virtually no or reduced activity of the enzyme required to break down galactose. Infants must be on a soy-based or elemental formula. Some medical sources suggest lactose-free formula, but other medical sources state that these formulas have not been conclusively shown to be safe for infants and children with galactosemia.

Some parents may choose to have their child tested for galactosemia before they are born. This is known as prenatal diagnosis. If the gene change(s) that causes galactosemia are known in a family, then molecular genetic testing (which can detect these changes) can be used for prenatal diagnosis. A sample of tissue can be taken from the placenta to test for changes in the GALT gene. This test is called chorionic villus sampling. Another test is called amniocentesis, which involves taking a sample of the amniotic fluid that surrounds and protects a developing fetus. Cells known as amniocytes are taken from the fluid and studied for changes in the GALT gene. There are risks to the unborn baby of doing these tests before birth. Talk to your doctor or a genetic counselor in your area to discuss the risks and benefits of prenatal diagnosis.

For the most part, galactosemia is the only name doctors use to describe this disorder. Infrequently the disorder may also be known as:

In addition to a modified, special diet, infants and children may receive more therapies based on their specific symptoms. Speech therapy may be necessary for children with speech apraxia, which is the inability to for certain sounds and words because the brain cannot generate the commands to move the necessary body parts (e.g. tongue, jaw), or dysarthria, which is when there is a problem moving the muscles that control speech. Some children will need special education services and assessment to help with learning disabilities and developmental delays.

Some infants and children will need calcium and/or vitamin D supplementation. Hormone replacement therapies may also be used when there is a delay in puberty. Surgery may be necessary for cataracts. Antibiotic medications may be used to treat infection.

There are a few support groups or organizations for galactosemia that provide support, information, advice, referrals to physicians and medical centers, and up-to-date information on research and treatments. Support groups for galactosemia include Galactosemia Foundation, Galactosaemia Support Group (UK), the European Galactosemia Society, and the Australian Galactosaemia Support Network.

Infants with galactosemia show symptoms within the early stages of life. Despite treatment, they remain at risk for delays in reaching developmental milestones and speech problems. The first few years of a child’s life are critically important to a child’s development. Some children have struggled in school, particularly with reading and math. States have federally-funded early intervention programs that support families that have concerns or issues with their children’s development up to the age of three. Some states will continue to offer early intervention programs beyond the age of three. Other states will transition a child into school-based programs that can be provided at home. In some states, a child may be eligible for early intervention services at no charge. Other states may charge a fee, depending on the agencies involved.

Talk to your doctor and medical team about early intervention programs in your state and whether these resources will appropriate and beneficial for your child. The Centers for Disease Control and Prevention (CDC) provide information about early intervention programs and assistance.

There are three main types of galactosemia. Galactosemia type I, galactosemia type II, and galactosemia type III. The term ‘galactosemia" means too much galactose in the blood. People with these disorders lack functional copies of enzymes that are important in the break down (metabolism) of galactose. Galactose is a sugar. The body gets most of its galactose from the breakdown of lactose, the main sugar in milk. Galactose is supposed to be broken down further into another sugar called glucose (which is a main energy source for the body) and other molecules essential for the proper function of the body. Because people with galactosemia are missing an enzyme, galactose cannot be broken down and instead ends up building up in the body. When galactose builds up, it becomes toxic to the cells.

Galactosemia type I is also called classic galactosemia and it is the most common form.

Galctosemia type II is also called galactokinase (GALK) deficiency and affected infants or children may develop cataracts. They rarely develop any other symptoms.

Galactosemia type III is also called epimerase deficiency galactosemia or UDP-galactose-4’-epimerase (GALE) deficiency. This type is extremely rare. The symptoms and severity of this type can be different in one person when compared to another.

Some medical sources suggest lactose-free formula, but other medical sources state that these formulas have not been conclusively shown to be safe for infants and children with galactosemia. Talk to your physician and entire medical team including a nutritionist and dietician about what is best for you or your child.

A milk allergy is not the same as galactosemia. A milk allergy is when the immune system mistakenly attacks the proteins found in dairy (or other foods) because it thinks the body is in danger. Galactosemia is a rare genetic disorder in which the body does not produce an enzyme required to break down galactose. People with a milk allergy or galactosemia both must avoid milk products, but they are very different disorders.