A boy with trigonocephaly, cleft palate, multiple minor anomalies, flexion deformities of elbows, cryptorchidism, and severe muscular hypotonia had an unbalanced karyotype with duplication of the distal 17q and deletion of the tip of 2p. This was derived from a reciprocal translocation in the father, 46,XY,t(2;17)(p25;q24). The propositus had some findings observed in patients with distal dup(17q), while trigonocephaly not found in these patients may be associated with the terminal deletion of 2p including the locus of SOX11 gene. It is proposed that the major clinical findings of this patient are consistent with the phenotype characteristic of the Opitz "C" trigonocephaly syndrome.