WAGR syndrome is a rare genetic syndrome in which affected children are predisposed to develop Wilms tumour (a tumour of the kidneys), Aniridia (absence of the coloured part of the eye, the iris), Genitourinary anomalies, and mental Retardation. The G is sometimes instead given as "gonadoblastoma," since the genitourinary anomalies are tumours of the gonads (testes or ovaries).