Interstitial deletion 13q syndromes: a report on two unrelated patients.

A partial monosomy 13 by interstitial deletion was found in the complement of two patients with mental retardation and mild dysmorphic features. Neither of the patients had a retinoblastoma, even though the second patient had a 13q14 deletion. The karyotype-phenotype correlation in the two patients suggests the need to reconsider the clinical profile of these rare chromosomal syndromes in a large series of subjects.