Galactokinase deficiency is an inborn error of galactose metabolism. Untreated patients develop early onset, bilateral cataracts, which at this time appears to be the only consistent abnormality in galactokinase
deficiency. Rarely, additional clinical symptoms have been reported including asymptomatic hypoglycemia, mental retardation, failure to thrive, seizures, deafness, hepatomegaly, and hypercholesterolemia; however, it is unclear whether these additional abnormalities are a result of galactokinase enzyme deficiency. In one report of 18 affected patients, the authors report that additional symptoms seemed to be more prevalent in patients who were non-compliant with treatment. Treatment of patients with a lactose-free, reduced galactose diet results in prevention or, in some cases, regression of cataracts. Estimates of the frequency of galactokinase deficiency range from 1 in 2,200,00 to 1 in 40,000.1 The highest incidence has been found in the Romani population where the carrier frequency is estimated to be 1 in 47.