Galactose-1-phosphate uridyltransferase deficiency

Galactose-1-phosphate uridyltransferase deficiency

Galactose-1-phosphate uridyltransferase deficiency, also known as Classic Galactosemia, is a rare genetic metabolic disorder that affects the body's ability to process the sugar galactose properly. This condition is part of a group of disorders known as galactosemias, which result from the inability to metabolize galactose, a sugar found in milk and other dairy products.

Pathophysiology

The deficiency is caused by mutations in the GALT gene, which encodes the enzyme galactose-1-phosphate uridyltransferase. This enzyme is crucial in the Leloir pathway, the metabolic pathway responsible for converting galactose into glucose. In individuals with this deficiency, the accumulation of galactose-1-phosphate and other toxic substances occurs, leading to various symptoms and complications.

Symptoms

Symptoms of galactose-1-phosphate uridyltransferase deficiency typically appear shortly after birth and can include:

• Jaundice
• Hepatomegaly
• Vomiting
• Failure to thrive
• Cataracts
• Developmental delay

If untreated, the condition can lead to severe complications such as liver damage, sepsis, and even death.

Diagnosis

Diagnosis of galactose-1-phosphate uridyltransferase deficiency is usually made through newborn screening programs, which test for elevated levels of galactose in the blood. Confirmatory tests include measuring the activity of the GALT enzyme in red blood cells and genetic testing to identify mutations in the GALT gene.

Treatment

The primary treatment for this condition is a galactose-restricted diet, which involves eliminating lactose and galactose from the diet. This dietary management helps prevent the accumulation of toxic substances and alleviates symptoms. Lifelong adherence to the diet is necessary to prevent long-term complications.

Prognosis

With early diagnosis and strict dietary management, individuals with galactose-1-phosphate uridyltransferase deficiency can lead relatively normal lives. However, some may experience long-term complications such as speech difficulties, learning disabilities, and ovarian failure in females.

Research

Ongoing research is focused on understanding the genetic basis of the disorder, improving diagnostic methods, and developing new treatments. Gene therapy and enzyme replacement therapy are potential future treatments under investigation.

See also

• Galactosemia
• Metabolic disorders
• Newborn screening

NIH genetic and rare disease info

• NIH info on Galactose-1-phosphate uridyltransferase deficiency

Galactose-1-phosphate uridyltransferase deficiency is a rare disease.