Galactokinase deficiency, or galactosemia type II, is a disease that impairs the body’s ability to metabolize galactose, a sugar found in milk.
The primary symptom is cataracts, clouding the eye’s lens and leading to vision impairment. Cataracts develop in both eyes during infancy. While other symptoms like low blood sugar, intellectual disability, and growth issues have been reported, their connection to galactokinase deficiency remains unclear. This condition is generally milder than other forms of galactosemia. Management involves regular blood tests to monitor galactose-1-phosphate levels and a lifelong diet free of galactose-containing foods, especially milk and milk products. Infants should be fed with galactose-free formulas. Parents must educate children to read product labels to avoid galactose-containing foods. Dietary restrictions often resolve cataracts, and calcium supplements may be necessary to prevent calcium deficiency in affected individuals.
This condition is caused by pathogenic (disease-causing) variants in the GALK1 gene and exhibits autosomal recessive inheritance. This means that both parents must be carriers to have a 25% chance to have a child with the condition. The risk of being a carrier is based on a person’s ancestry or ethnic background.