Galactosemia is a disorder that can cause many problems in newborns and can be life-threatening if left untreated. It is important to timely diagnose and start treatment in order to slow down the progression of the pathology.
There are many good things in breast milk that babies need - key nutrients, hormones and antibodies that protect against disease and keep them healthy.
But some babies are born with galactosemia. It is a rare carbohydrate metabolism-related disorder in which the processing of galactose (one of the sugars in breast milk and formula) is impaired. With galactosemia, the blood contains too much galactose. The signs and symptoms of this disease are a consequence of the inability to use galactose for energy production. Its build-up can lead to serious complications and health problems.
The disease follows an autosomal recessive mode of inheritance, which results in a deficiency of the enzyme responsible for adequate breakdown of galactose.
Goppert first described the disease in 1917, and its cause as a malformation of galactose metabolism was identified by a group led by Hermann Kalkar in 1956.
The incidence is about 1 in 60,000 deliveries.
Types of galactosemia
Researchers have identified several types of galactosemia. These pathologies are caused by mutations in a specific gene and affect various enzymes involved in the destruction of galactose.
Classical galactosemia, also known as type I, is the most common and most severe form of the disease. If infants with classic galactosemia are not treated promptly with a low-galactose diet, life-threatening complications appear several days after birth. Affected infants usually have difficulty feeding, lack of energy, inability to gain weight and growth as expected, yellowing of the skin and whites of the eyes (jaundice), liver damage, and abnormal bleeding. Other serious complications of this condition can include overwhelming bacterial infections (sepsis). Affected children are also at increased risk of developmental delays, clouding of the lens of the eye (cataracts), and mental disability. A woman with classic galactosemia may develop reproductive problems caused by early loss of ovarian function.
Galactosemia type II (also called galactokinase deficiency) and type III (galactose epimerase deficiency) cause different symptoms. Galactosemia type II results in fewer medical problems than the classic type. Affected infants develop cataracts, but otherwise have several long-term complications. Signs and symptoms of type III galactosemia range from mild to severe and can include cataracts, stunted growth and development, mental disability, liver disease, and kidney problems.
Causes
Galactosemia is caused by mutations in genes and enzyme deficiencies. This causes galactose to accumulate in the blood. It is an inherited disorder. Parents are considered carriers of the disease, they have one copy of the mutated gene, but they usually do not have signs and symptoms of the condition.
Galactosemia is a recessive genetic disorder, so two copies of the defective gene must be inherited for the disease to appear. This usually means that a person inherits one defective gene from each parent.
When planning a pregnancy, expectant parents can undergo a genetic test for galactosemia. If they happen to be carriers, that doesn't mean they need to avoid galactose. But this means that parents can pass this disease on to their children.
Genetic changes
Mutations in the GALT, GALK1 and GALE genes cause galactosemia. These genes carry instructions for making the enzymes needed to break down galactose from the diet. These enzymes break down galactose into other simple sugars, glucose, and other molecules that the body can store or use for energy.
Mutations in the GALT gene lead to classic galactosemia (type I). Most of these genetic changes almost completely eliminate the activity of an enzyme produced by the GALT gene, preventing the normal processing of galactose and leading to life-threatening signs and symptoms of this disorder. Another mutation in the GALT gene, known as the Duarte variant, decreases but does not eliminate enzyme activity. People with the Duarte variant have much milder features of galactosemia.
Type II galactosemia occurs due to mutations in the GALK1 gene, while mutations in the GALE gene underlie type III galactosemia. Like the enzyme derived from the GALT gene, the enzymes derived from the GALK1 and GALE genes play an important role in the processing of galactose. A deficiency in any of these critical enzymes allows galactose and related compounds to build up to toxic levels in the body. The accumulation of these substances damages tissues and organs, which leads to the characteristic features of galactosemia.
Symptoms
Newborns with severe deficiencies in the enzyme that breaks down galactose usually have:
- poor growth in the first few weeks of life;
- jaundice;
- bleeding due to coagulopathy (a violation of blood clotting);
- liver dysfunction and / or hepatomegaly (enlarged liver);
- cataract (sometimes already in the first days of life);
- lethargy;
- hypotension;
- sepsis (blood poisoning with E coli);
- seizures;
- edema of the brain.
Surprisingly, ascites (accumulation of fluid in the abdomen) can also be found in early infancy. In some patients, ascites are found already in the first days of life.
In an infant with cataracts, galactosemia should be excluded. An ophthalmologist's examination is necessary, because some cataracts, especially congenital ones, are visible only with a slit lamp (an apparatus for performing eye biomicroscopy).
Vitreous hemorrhage (transparent, filling the entire volume of the eyeball located behind the lens) is a common complication of the disease. There is a mysterious link between E coli sepsis and galactosemia. Galactosemia should be a priority in the differential diagnosis of newborns with sepsis caused by infection with this pathogen.
Learning problems and speech defects are common; mastery of speech may be delayed.
Diagnostics
In Russia, in accordance with modern standards, newborns are screened for some hereditary diseases, including galactomysia. None of these manifestations are specific to galactosemia, which often results in delayed diagnosis. Fortunately, most children are diagnosed with the disease at newborn screening. If the child's family has members with galactosemia, doctors may do a prenatal test by taking a sample of fluid around the fetus (amniocentesis) or from the placenta (chorionic villus sampling).
A galactosemia test is a blood test (from the heel of a baby) or urine that tests for the presence of three enzymes needed to change the sugar galactose found in milk and dairy products into glucose, a sugar that the human body uses for energy. All of these enzymes are absent in a patient with galactosemia. This results in large amounts of galactose in the blood or urine.
Detection of the disorder by newborn screening is independent of protein or lactose intake. It is accurate for identifying galactosemia.
Treatment
Prompt treatment is needed to prevent serious health problems and mental disabilities.
Babies and children who do not completely have the GALT enzyme, or have less than 10% of the normal amount, should follow a special diet. They need to avoid all foods containing lactose and galactose. Milk and all dairy products should be replaced with a lactose-free formula.
The following are guidelines for children with classic galactosemia:
Diet without lactose and galactose
It is recommended that you follow a lactose and galactose free diet plan throughout your life. Lactose or galactose can be found in the following foods to avoid:
- milk and all dairy products;
- Processed and prepackaged foods often contain lactose
- tomato sauces;
- some sweets;
- some medicines - tablets, capsules, sweetened liquid drops that contain lactose as a filler;
- some fruits and vegetables also contain galactose;
- any food or medicine containing lactulose, casein, caseinate, lactalbumin, whey.
It is recommended that you see a dietitian to help develop a meal plan that will allow your child to avoid lactose and galactose while maintaining the correct amount of protein, nutrients and energy.
Your child's meal plan will depend on many factors such as age, body weight, general health, and blood test results.
Proprietary Lactose Free Blend
Newborns with galactosemia should be fed a special lactose-free formula. The most common foods used for babies with galactosemia are those made with soy protein isolate. Soy milk contains galactose and should not be used.
Mother's milk also contains lactose and is not recommended for babies diagnosed with this condition. However, some babies with galactosemia Duarte are still able to drink breast milk.
Calcium supplements
Because children with galactosemia do not eat dairy products, calcium intake is too low. Therefore, patients are often advised to take calcium supplements so that they get enough of this mineral every day.
Some doctors also advise adding vitamins D and K in addition.
Do not use any medications or supplements without the advice of your doctor.
Health monitoring
Affected children usually require regular blood and urine tests. These tests are used to detect toxic substances produced when galactosemia is not under control. The test results will help the healthcare professional to tailor the treatment to meet your child's needs.
Galactosemia can increase the risk of contracting pathogens, so fighting infections when they do occur is essential. Antibiotics or other medications may be required.
It is also necessary to control mental development, the formation of speech and language skills. If a child shows delays in certain areas of learning or speech, additional assistance should be arranged.
Due to the fact that the body also produces some amount of galactose, symptoms will not be completely eliminated by removing all lactose and galactose from the diet. Researchers are working to find a cure to reduce the amount of galactose produced by the body, but there is currently no effective way to do this.
When treatment is started before the child is 10 days old, there is a much better chance of normal growth and development. Some children who receive early treatment may have growth retardation, but most have reached normal adult height.
Even with careful treatment from an early age, individual patients with classic galactosemia have learning and developmental delays and may need extra help at school. Sometimes there are delays in speech development and language acquisition. Some have delayed motor skills such as walking, coordination, and balance problems.
Also, even with proper treatment, a girl with galactosemia has a higher risk of having a delayed start of her menstrual cycle and premature ovarian failure.
If treatment is started after 10 days of life, delays or learning problems are more likely. The level of latency varies from patient to patient. Treatment is still important, even if started late, as it can help prevent further symptoms.
Galactosemia and lactase deficiency
Many people can confuse the two terms. Some might even think that these 2 disorders are the same, as both are related to problems with the breakdown of milk sugar.
However, galactosemia and lactase deficiency are very different.
| Criterion | Galactosemia | Lactase deficiency |
| A substance that the body is unable to process | Galactose | Lactose |
| Disorder type | Genetic disease | The body slowly loses its ability to produce the enzyme lactase |
| The cause of the disorder | Deficiency in the production of multiple enzymes | Deficiency in the production of 1 enzyme, in particular lactase |
| Carbohydrates for elimination | Galactose should be excluded. The body can digest lactose but cannot metabolize galactose when it enters the bloodstream | Large amounts of lactose should be avoided as the body cannot break it down |
| Treatment | There is no known cure other than eliminating food containing galactose | Enzyme preparations can be used to digest lactose |
Conclusion
Galactosemia is a rare inherited disorder that affects how galactose is broken down in the body. If the disease is not diagnosed at an early age, then complications can be serious.
Following a galactose-free diet is an important part of treatment. Discuss additional dietary restrictions and other concerns with a healthcare professional.
