As much as 40% of early-onset cataracts may have a genetic basis [2], either as a recognized feature of over 50 genetic syndromes, involving other ocular defects (e.g., microphthalmia) and systemic abnormalities (e.g., galactokinase deficiency), or more often as an isolated lens phenotype with autosomal dominant inheritance (Online Mendelian Inheritance in Man; OMIM). This evidence concerns the gene GALK1 and cataract.