Abstract
Purpose: :
Several enzyme defects of the galactose pathway may lead to congenital cataract formation. The purpose of this study was to determine the frequency of disorders in galactose metabolism in different morphological forms of congenital cataract.
Methods: :
From 1998 on, in all children undergoing surgery for congenital cataract of unclear etiology, lens material and blood samples were investigated for enzyme defects or elevated levels of galactitol as an indirect parameter for a disorder in galactose metabolism. The investigated enzymes were the galactokinase, the UDP-galactose-epimerase and the galactose-1-phosphate-uridyl-transferase. The type of congenital cataract formation was classified by split lamp examination before or during surgery.
Results: :
Between 1998 and 2009, 79 patients with congenital cataract underwent surgery (mean age at surgery 50 months, 42 females, 37 males). In 23 patients (29%, mean age at surgery 51 months, 14 females, 9 males), there was an association with another eye disease (Rieger-syndrome, persistent hyperplastic primary vitreous), maternal infection during pregnancy.or chromosomal disorder (trisomie,turner-syndrome). In 56 children (71%, mean age at surgery 49 months, 28 females, 28 males) with no evident etiology for congenital cataract lens material and blood samples were investigated for disorders in galactose metabolism. 8 children showed a reduced activity of UDP-Galactose-4-epimerase, 1 child showed a defect of galactokinase and 2 childs revealed higher levels of galactitol without detectable enzyme defects. In these cases the most common type of cataract was a zonular cataract in 5 eyes and a pulverulent cataract in 3 eyes.
Conclusions: :
In about 20% of children with congenital cataract of unknown etiology a defect in galactose metabolism was found. The percentage in this study is 3fold higher than the percentage of 6% reported in the literature. Thus, in patients with unexplained congenital or developmental cataract, investigations of enzymes and polyols of galactose metabolism are recommended and may help to decide about dietary intervention.
Keywords: cataract • clinical (human) or epidemiologic studies: prevalence/incidence • metabolism