Galactose cataract is an autosomal recessive hereditary disorder.
Etiology
The condition arises from a deficiency in galactose-1-phosphate uridyltransferase and galactokinase, which prevents the conversion of galactose into glucose, leading to the accumulation of galactose in the body. Within tissues, galactose is reduced to galactitol by aldose reductase. Galactitol exhibits high osmotic activity, and its water absorption within the lens results in lens opacification.
Clinical Features
The condition may develop within several days or weeks after birth. It often presents as perinuclear cataracts.
Diagnosis
Screening for galactose in the urine is necessary when congenital cataracts are observed in infants. Measurement of galactose-1-phosphate uridyltransferase activity in red blood cells can confirm whether a deficiency of this enzyme is present. Radiochemical methods may be used to determine galactokinase activity, which can assist in the diagnosis.
Treatment
The progression of the condition can be controlled by adopting a lactose- and galactose-free diet.