Two cases of interstitial deletion of the long arm of chromosome 1: del(1)(q21----q25) and del(1)(q41----q43).

Two unrelated children, one with a proximal interstitial deletion 1 (1(pter----q21: :q25----qter] and the other one with a distal interstitial deletion 1 (1(pter----q41: :q43----qter] are presented. The clinical features of the patient with a proximal deletion (q21-q25) correspond with those of eight earlier reported cases with a deletion 1q21/22/23----q25. The second patient with the distal interstitial deletion (q41-q43) is the first case published as far as we know. The clinical characteristics of the latter patient are compared with those of six cases with a terminal deletion 1q with at least one common band missing (1q42).