Two mentally retarded brothers with partial trisomy 3q show clinically similar malformations and deformities : dwarfism, bushy eyebrows, eversion of the nostrils, low inserted ears, high palate, microgeny, low hair insertion, short and broad hands with proximally inserted thumbs, clinodactylia of the 5th finger, syndactylies, mostly arch patterns on the digital pulps, muscular hypotonia, joint relaxation and cryptorchism. Both children had fits of convulsions. The younger boy showed, moreover, a perception deafness. The mother, the maternal grand-mother as well as the phenotypically normal sister of the patients revealed a balanced translocation 3/22 with a karyotype : 46,XX,t(3;22) (q25;p11).