Short rib-polydactyly syndrome,Majewski type,in two male siblings

Summary C-band polymorphisms of chromosomes 1, 9, and 16 were investigated in (1) 165 newborn infants, (2) 93 Down's syndrome patients, (3) 69 patients with acquired mental retardation, (4) 54 idiopathic patients, and (5) 48 idiopathics with multiple congenital malformations. The C-band size of chromosomes 1 and 9 showed a similar nonnormal distribution in all five groups. A significantly higher frequency of C bands, some of which were located on the short arm of chromosome 9, was observed in the groups of patients with Down's syndrome and with idiopathic mental retardation.