[Two neonates with congenital aniridia: the necessity of genetic investigation]

Two female neonates were diagnosed post partum with bilateral aniridia. The first patient had the familial form, caused by a point mutation in the paired box 6 (PAX6) gene. The second patient had a sporadic aniridia caused by a de novo microdeletion involving both the PAX6 gene as well as the Wilms tumour suppressor-I (WT1) gene. This made screening for the presence of a Wilms tumour necessary. The second patient died several months after birth, due to respiratory insufficiency. Aniridia is a rare developmental disorder of the eye, with absence of most of the iris tissue, caused by an abnormality in the PAX6 gene on chromosome 11p13. Familial aniridia is usually due to a point mutation of the PAX6 gene, which causes solely ocular abnormalities. Sporadic aniridia is caused by a de novo deletion or microdeletion of chromosome 11p13, which affects not only the PAX6 gene but also the adjacent WT1 gene. In these patients, the Wilms tumour, aniridia, genitourinary anomalies, and mental retardation (WAGR) syndrome can be present, and screening for a Wilms tumour is indicated. Unless previous investigation of a family member has demonstrated the WT1 gene to be normal, chromosome studies should always be performed in patients with aniridia.