Trisomy for a small terminal segment of chromosome 6q produces a characteristic syndrome of malformations and dysmorphic signs which, on the basis of comparison with a previously published case, may be suspected on clinical grounds. The present case concerns a 7-year-old boy, the son of a carrier mother t(6;14)(q25;qter). The main symptoms are: very severe physical and mental retardation, turricephaly, Cupid's bow mouth with narrow lips, almond-shaped eyes with narrow palpebral fissures and ptosis, micropenis with absence of scrotum, club feet, hammer toes, and extension contractures. In addition, there are a great many minor dysmorphic features.