What is Galactokinase Deficiency?
Galactokinase deficiency, also called galactosemia type II, is a treatable inherited disease that reduces the body's ability to metabolize galactose, a simple sugar found in milk. The primary symptom is cataracts (clouding of the lens of the eye), which can cause vision impairment. Cataracts are due to the build up of a substance in the lens of the eye called galactitol. Cataracts in affected individuals are usually seen in both eyes and typically develop in infancy within the first few weeks or months. Galactokinase deficiency is anticipated to be milder with better outcomes than another more severe forms of galactosemia.
Other, less common symptoms have been reported in a few affected individuals, such as low blood sugar, intellectual disability, and problems with growth; however, it is unclear whether they were caused by galactokinase deficiency in these individuals.
How common is Galactokinase Deficiency?
Approximately 1/40,000 - 1/370,000 newborns are affected with galactokinase deficiency. It is seen more frequently in the Romani populations across Europe. The number of affected individuals may vary across populations.
How is Galactokinase Deficiency treated?
People with classic galactosemia must monitor their galactose-1-phosphate levels with regular blood tests and follow a lifelong diet free of milk, milk products, or other foods containing galactose. Infants should be fed with galactose-free formulas. As children learn to feed themselves, parents must teach them how to read product labels so they can avoid any food containing milk, dry milk, milk products, and other galactose-containing foods. Often they require calcium supplements to avoid calcium deficiency. Dietary restriction often resolves the cataracts in affected individuals.
What is the prognosis for a person with Galactokinase Deficiency?
The prognosis of galactokinase deficiency is excellent if affected individuals continue a galactose free diet. With treatment, cataracts can be prevented or at least partially resolved if they have started to form prior to treatment.