Galactosemia is a genetic condition that causes an inability to break down a sugar called galactose. Galactose is produced during the breakdown of lactose, which is the main sugar found in dairy products. Galactose is normally further broken down into smaller components that the body uses for energy.
Patients with galactosemia cannot break down galactose, and as a result unhealthy levels of galactose may build up in the body. Because galactose is not properly metabolized, or broken down, galactosemia is classified as a metabolic disorder.
Galactosemia is caused by a mutation, or error, in any of the three genes that provide instructions for making the enzymes that break down galactose. Galactosemia is inherited or passed down among family members as an autosomal recessive trait, meaning that an individual must inherit two copies of the mutated gene for the condition to develop. Mutations in several genes have been linked to galactosemia.
Galactosemia affects about one in 30,000 to one in 60,000 newborns worldwide and appears to affect females and males equally. Signs of galactosemia may become apparent soon after birth. Infants with galactosemia may experience vomiting, liver failure, and bacterial infections. Severe bacterial infections may be fatal. Some infants with a milder form of galactosemia may develop cataracts or clouding of the lens of the eye.
Liver problems may include enlargement and cirrhosis, in which scar tissue replaces healthy liver tissue. Some people with galactosemia may develop liver failure, which could be life-threatening if not recognized and treated appropriately.
Currently there is no known cure for galactosemia. Treatment generally focuses on restricting dietary intake of lactose and galactose. If galactose levels are successfully controlled, most people with galactosemia can live normal lives.
Galactose, galactose-1-phosphate uridyltransferase, galactose-1-phosphate uridyl transferase deficiency, galactokinase 1, GALE gene, GALK1 gene, GALT gene, inherited genetic condition, lactose, learning disabilities, liver failure, metabolic disorders, UDP-galactose-4-epimerase.
types of the disease
Type 1 galactosemia: Type 1 galactosemia is the most common form of the disease. This form of the disease is caused by mutations in the GALT gene. Infants with type 1 galactosemia may experience vomiting, liver failure, and bacterial infections. Liver problems may include liver enlargement or cirrhosis, a condition in which scar tissue replaces healthy liver tissue.
Type 2 galactosemia: Type 2 galactosemia is caused by mutations in the GALK1 gene. This form of the disease is less severe than type 1 galactosemia. Infants with type 2 galactosemia may develop cataracts or clouding of the lens of the eye but typically have few other medical problems.
Type 3 galactosemia: Type 3 galactosemia is caused by mutations in the GALE gene. Symptoms of type 3 galactosemia vary from patient to patient and may include cataracts, delayed growth and development, intellectual disability, or liver disease.