[Pure trisomy 13q13-qter caused by aneusomic recombination of a maternal pericentric inversion].

A 17-year-old girl with a severe mental retardation and facial dysmorphism was found to be carrier of an abnormal chromosome no. 13. Her mother and several other members of her family carry a pericentric inversion of chromosome no. 13. The abnormal 13 of the proposita was shown to result of "aneusomie de recombinaison" of the inverted chromosome no. 13. Biochemical, hematological, and clinical features contribute to the establishment of the clinical map of chromosome 13.