Brief clinical report: two children with de novo del(9p).

We describe two patients with characteristic manifestations of the del(9p) syndrome. Among the prominent manifestation are moderate mental retardation, trigonocephaly, flat nasal bridge, anteverted nostrils, long philtrum, square and hyperconvex nails, and apparently long digits. The metacarpophalangeal pattern profiles of the patients showed that the clinical impression of long fingers may be due to relative shortness of the metacarpals rather than to elongation of the phalanges.