Recently, a new clinically recognizable syndrome resulting from a small interstitial deletion of 17p [del(17)(p11.2p11.2)] was described in ten unrelated patients. We have identified six additional patients with similar cytogenetic and phenotypic abnormalities. Consistent clinical manifestations include 1) brachycephaly with a broad face and nasal bridge, 2) flat midface, 3) short, broad hands, and 4) mental retardation associated with hyperactivity and often self-destructive behavior. The craniofacial and hand anomalies are reminiscent of several craniosynostosis syndromes. Most patients also had growth deficiency and several other (more variable) congenital malformations. Chromosome studies with special attention to 17 should be performed in any patient with a similar phenotype.