De novo chromosome translocation t (2; 11) (p25.1; p13) in a patient with aniridia and genitourinary abnormalities.

Aniridia is a rare condition occurring in 1 in 64,000 to 1 in 96,000 live births. Approximately one third of cases are sporadic and carry a 30% risk of Wilms' tumor developing before the age of 5. The remaining 66% are inherited in an autosomal dominant fashion. The aniridia candidate gene (PAX6) has a key role as a master regulator in the development of eye and central nervous tissues. The Wilms' tumor predisposing gene (WT1) plays an important role in the development of genitourinary tract diseases such as hypospadias, cryptorchism, horse-shoe kidney, and Wilms' tumor. The WT1 and PAX6 genes are about 700 kb apart, with the WT1 gene located centromeric to PAX6 in chromosome 11p13. We report a patient with incomplete aniridia, ptosis, hypospadias, and cryptorchism. Cytogenetic analysis revealed the presence of a de novo reciprocal translocation 46, XY, t (2; 11) (p25.1; p13) without microscopic deletion. We suggest that haploinsufficiency in PAX6 and WT1 genes resulted in aniridia and associated genitourinary abnormalities.