A ring chromosome, diagnosed by quinacrine fluorescence as No. 9, in a mentally retarded girl

Abstract

A ring chromosome No. 9 identified by quinacrine staining was found in a 22‐year‐old mentally retarded girl with low stature, fissure of the palate, protruding lower lip and valgus deformity of the knees. The patient showed heterozygosity (type II) for cystinuria. The ring was unstable and showed different configurations.