Del (9p) syndrome: report of four cases

The chromosome 9p deletion [del (9p)] syndrome is a rare but specific clinical entity. The clinical manifestations include dysmorphic facial features (trigonocephaly, midface hypoplasia, upward-slanting palpebral fissures, and a long philtrum) and psychomotor retardation. Four patients with characteristic features of del (9p) syndrome were reported. Cytogenetic analysis showed a de novo deletion of the short arm of chromosome 9 with the breakpoint being located at band 9p22 in all cases. Fluorescence in situ hybridization using painting probe for chromosome 9 excluded translocations involving 9p and another chromosome. Long-term follow-up in these patients showed that neuro-psychiatric problems were common in their later ages.