Wilms' tumor, malformative syndrome, mental retardation and de novo constitutional translocation, t(7;13)(q36;q13).

An apparently balanced de novo constitutional translocation (7;13) (q36;q13) was detected on peripheral lymphocytes and fibroblasts of a 14-month-old boy. The patient presented a facial dysmorphism with hydrocephaly and mental retardation associated with a Wilms' tumor. A pure coincidence of random association cannot be ruled out but one can equally assert the plausibility of a minimal unnoticed deletion or a position effect.