Classic galactosemia

Classic Galactosemia Classic galactosemia is a rare genetic metabolic disorder that affects an individual's ability to metabolize the sugar galactose properly. This condition is part of a group of disorders known as galactosemias, which are characterized by the inability to process galactose, a sugar found in milk and other dairy products.

Etiology

Classic galactosemia is caused by mutations in the GALT gene, which encodes the enzyme galactose-1-phosphate uridylyltransferase (GALT). This enzyme is crucial for the proper metabolism of galactose. When GALT is deficient or absent, galactose-1-phosphate accumulates in the body, leading to the symptoms associated with the disorder.

Pathophysiology

The accumulation of galactose-1-phosphate and other toxic substances in the body due to the lack of GALT activity leads to the various symptoms of classic galactosemia. These substances can cause damage to the liver, kidneys, brain, and other organs.

Clinical Presentation

Symptoms of classic galactosemia typically appear shortly after birth and may include: - Jaundice - Vomiting - Poor feeding - Failure to thrive - Lethargy - Hepatomegaly - Cataracts If left untreated, classic galactosemia can lead to serious complications such as intellectual disability, speech problems, and liver disease.

Diagnosis

Classic galactosemia is diagnosed through newborn screening programs, which test for elevated levels of galactose or galactose-1-phosphate in the blood. Confirmatory testing involves measuring the activity of the GALT enzyme or genetic testing to identify mutations in the GALT gene.

Treatment

The primary treatment for classic galactosemia is a strict galactose-free diet, which involves eliminating all sources of galactose from the diet. This includes avoiding milk, dairy products, and other foods containing galactose. Early dietary intervention can prevent many of the acute symptoms and complications of the disease.

Prognosis

With early diagnosis and dietary management, individuals with classic galactosemia can lead relatively normal lives. However, some long-term complications may still occur, such as speech and learning difficulties, ovarian failure in females, and neurological impairments.

Research and Future Directions

Research is ongoing to better understand the pathophysiology of classic galactosemia and to develop new treatments. Gene therapy and enzyme replacement therapy are potential future treatments that are being explored.

See Also

• Galactosemia
• Metabolic disorders
• Newborn screening

NIH genetic and rare disease info

• NIH info on Classic galactosemia

Classic galactosemia is a rare disease.