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HomeHealth articlesgalactosemiaWhat Is Galactosemia?

Galactosemia - Causes, Symptoms, and Treatment

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Galactosemia is a rare metabolic disorder affecting the blood's galactose process. It can be life-threatening in infants. Read the article to know more.

Medically reviewed by

Dr. Basuki Nath Bhagat

Published At June 27, 2023
Reviewed AtJanuary 2, 2024


Galactosemia is a rare genetic disorder that affects the galactose metabolism process in the body. A small amount of galactose is found in many foods. Galactose is a simple sugar found in milk, yogurt, cheese, and other dairy products. When combined with glucose, it forms a large part of sugar known as lactose. Lactose is found in many dairy products, including breast milk and baby formula. Breast milk is full of nutrients and hormones that the baby need. In addition, the antibodies present in breast milk keep the baby healthy and protect them from several diseases. Unfortunately, many newborns are born with a disorder that prevents them from processing galactose in the blood and converting them into energy. A gene mutation, the so-called autosomal recessive disorder, causes the disease. The first case of galactosemia was reported in 1908. Around the world, the condition affects 40,000 to 60,000 newborns. It can lead to various complications and life-threatening problems if left untreated. However, with early diagnosis, the newborn can lead a healthy and everyday life.

What Are the Different Types of Galactosemia?

There are mainly four types of galactosemia disorders:

  • Type 1 or Clinical Variant or Classic Galactosemia: It is the most common and severe type of galactosemia. This type of galactosemia is caused due to a mutation in the galactose-1 phosphate uridyl transferase (GALT) gene. GALT is responsible for processing the enzymes that help in the breakdown of galactose into glucose, and the body uses it for energy. The gene mutation eliminates the enzyme activity, and the body cannot process the galactose. Classic galactosemia in infants shows feeding and growth difficulties. In addition, affected females show a loss of function of ovaries.

  • Type 2 or Galactokinase Deficiency: Galactokinase gene mutation may lead to type 2 galactosemia. The gene helps in galactose metabolism. Therefore, it causes fewer medical issues than classic galactosemia. However, affected infants may develop cataracts.

  • Type 3 or Galactose Epimerase Deficiency: Galactose epimerase gene plays an essential role in galactose metabolism. A deficiency of genes may lead to the accumulation of galactose in the body. The symptoms vary from mild to severe cataracts, liver and kidney problems, and delay in development.

  • Type 4 or Duarte Galactosemia: It is due to the GALT gene mutation. It reduces the enzyme function in galactose metabolism. As a result, affected people show some digestive food difficulties.

What Are the Causes of Galactosemia?

Galactosemia is a genetic disorder. It is caused due to gene mutations and deficiency of enzymes. The condition may be inherited from both parents. However, each parent may have one copy of the mutated gene and can transfer it to their children. The parents do not show symptoms unless both copies of the galactosemia gene are mutated. The mutated gene fails to produce the enzyme that helps in the breakdown of glucose to galactose for energy. This can lead to the accumulation of galactose in the body. The three different types of genes are involved in the mutation and lead to galactosemia. The genes are galactose-1 phosphate uridyl transferase (GALT), deficiency of galactose kinase (GALK), and lack of galactose-6 phosphate epimerase (GALE).

If both parents are carriers of the mutated gene, then there is a 25 % chance of inheriting galactosemia. The condition can affect all around the world, including all ethnic groups.

How Does Galactosemia Affect a Child’s Body?

When the child's body cannot break down galactose in the food, it builds up in the blood. Galactosemia is the formation of galactose in the blood. The excess formation of galactose in the blood may overflow in other places. As a result, an alcohol derivative enzyme involved in the conversion of galactose to galactitol can cause severe damage to the tissues and organs. If left untreated, it may lead to side effects, including cataracts, developmental delays, speech difficulties, kidney disease, liver failure, premature loss of ovarian function, neurological impairments, and gross motor difficulties.

If the children receive early diagnosis and treatment, they grow adequately. However, some children may feel trouble even on a galactose-free diet because the body cannot eliminate the galactose from the body. In addition, the average amount of galactose produced in the body causes problems. As a result, children receiving treatment may have speech impairment, behavioral issues, balance coordination problems, learning disabilities, tremors, and hormonal deficiencies.

How Does Galactosemia Affect the Adult Body?

Only those adults with galactosemia can live everyday lives, who do not experience symptoms as children. However, some signs may come and go depending on the restriction of the diet in adult life. Most women assigned the female at birth who suffers from galactosemia may have an early loss of ovarian function even with treatment. As a result, the females may face difficulties getting pregnant and carrying a baby in the womb. Hormone replacement may help with fertility problems.

What Are the Signs and Symptoms of Galactosemia?

The signs and symptoms may be mild to severe, including

  • Vomiting.

  • Lethargy.

  • Weakness.

  • Weight loss.

  • Jaundice.

  • Enlarged liver.

  • Loss of appetite.

  • Diarrhea.

  • Abdominal swelling.

  • Swelling around the brain.

How Can Galactosemia Be Diagnosed?

Galactosemia can be diagnosed with tests, and it is a part of screening in newborns. In addition, the doctor may advise blood tests. The blood can be taken by pricking a needle in the baby’s heel after 24 hours of birth. The blood test will show a decrease in GALT enzyme in the case of galactosemia. In addition, a genetic test may help in the diagnosis of the type of galactosemia.

How Can Galactosemia Be Treated?

The most common and only treatment is to eliminate galactose from the diet. Galactose contains lactose, so the doctor may advise avoiding dairy products and alternatively prescribe calcium and vitamin D supplements to cover up the lack of dairy products. In addition, it may improve bone density in people. Some children may need speech therapy as a part of treatment. In addition, individual education plans may benefit the children from speech therapy.


Galactosemia is a genetic disorder affecting mainly newborns. The disease may be inherited from one or both parents due to the GALT and GALE gene mutations. The symptoms in the newborn include speech impairment, developmental delay, cataracts, and premature loss of ovarian function. Early diagnosis and treatment may help prevent liver failure and organ damage. Healthcare providers may diagnose and treat the condition early to avoid severe life-threatening complications.

Frequently Asked Questions


What Is the Mode of Inheritance for Galactosemia?

The inheritance of classic and clinical variant galactosemia follows an autosomal recessive pattern. If a couple has already had an affected child, there is a 25 percent likelihood of having another affected child in each subsequent pregnancy.


What Is the Underlying Genetic Etiology of Galactosemia?

Galactosemia, a metabolic disorder, is primarily caused by mutations in the GALT gene. This gene is responsible for encoding the enzyme galactose-1-phosphate uridylyltransferase, which is essential for the proper metabolism of galactose. The deficiency of this enzyme results in the inability to metabolize galactose effectively.


Is Galactosemia Inherited as an Autosomal Dominant or Recessive Trait?

Galactosemia is a genetic disorder that follows an autosomal recessive pattern of inheritance. This means that an individual must inherit two copies of the non-functioning gene, one from each parent, to develop the condition. The disorder arises due to the body's inability to break down galactose, which is a constituent of lactose present in mammalian milk.


What Foods Are High in Galactose?

Honey, beets, cheese, yogurt, cherries, celery, kiwifruit, soy sauce, plums, and dried figs are among the foods with a high galactose concentration. Furthermore, food products made with cheese or milk, such as pizza and pudding, might have a high galactose concentration.


What Is the Underlying Cause of Galactosemia?

Three distinct forms of galactosemia have been recognized, each attributed to a specific mutation in the GALE, GALK1, and GALT genes. These genes play a crucial role in synthesizing the enzymes necessary for the metabolic breakdown of galactose.


How Is Galactosemia Diagnosed?

The identification of classic galactosemia and clinical variant galactosemia is determined through the identification of increased levels of galactose-1-phosphate in erythrocytes, decreased activity of the galactose-1-phosphate uridylyltransferase (GALT) enzyme in erythrocytes, and the presence of two pathogenic variants in the GALT gene.


What Are the Criteria for Diagnosing Galactosemia?

Clinical diagnosis of galactosemia is indicated and further supported by elevated galactose levels and identifying reducing substances in the urine, such as galactose and galactose 1-phosphate. DNA analysis or enzyme analysis of red blood cells, hepatic tissue, or both can be performed to confirm the diagnosis.


What Are the Initial Symptoms of Galactosemia?

Infants with galactosemia may exhibit initial symptoms such as jaundice, inadequate feeding, vomiting, and lethargy. Failure to provide appropriate treatment can result in the development of more serious complications, including impairments in development and damage to the liver.


What Is the Most Common Infection Associated With Galactosemia?

Infants diagnosed with galactosemia may exhibit symptoms within the initial days of their lives upon consuming lactose-containing formula or breast milk. This can lead to the development of a severe blood infection caused by the bacteria E. coli.


Is Galactosemia Curable?

Galactosemia is not curable but can be managed through a strict galactose-free diet. With early diagnosis and adherence to the diet, individuals with galactosemia can lead relatively normal lives.


Can Someone Lead a Regular Life if They Have Galactosemia?

Individuals who receive an early diagnosis and diligently abstain from consuming milk products and other food items containing lactose have the potential to lead a fairly typical life. Those with galactosemia can maintain a regular lifestyle by effectively managing their condition. Adhering strictly to a diet devoid of galactose is of utmost importance to prevent the buildup of galactose and its harmful byproducts.


Can Galactosemia Patients Consume Milk?

Galactosemia patients are usually instructed to steer clear of any food items that contain galactose, such as dairy products and milk. Adhering to a galactose-free diet is essential for effectively managing the condition throughout one's life. Instead of cow's milk, they may be provided with specialized formulas or milk substitutes devoid of galactose.
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Dr. Basuki Nath Bhagat
Dr. Basuki Nath Bhagat

Family Physician


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