Long arm deletion of chromosome 22

Abstract

A deletion of a G group chromosome was first observed in an infant in 1964. In 1968 it was suggested that there were two distinct syndromes, one in which the physical features were caused by an abnormality of chromosome 21 (G deletion syndrome I) and the other in which an abnormality of chromosome 22 was the cause of the abnormal physical features (G deletion syndrome II). The characteristics associated with G deletion syndrome I are: mental retardation, hypertonia, microcephaly, large or low set ears, skeletal malformations, and growth retardation. The characteristics associated with G deletion syndrome II are: mental retardation, hypotonia, epicanthic folds, and syndactyly of the toes. These chromosome abnormalities and their associated physical characteristics are somewhat variable, as noted by Maeda et al. They concluded that the physical features associated with G deletion syndrome I are constant and represent a clinically distinct syndrome. The physical characteristics associated with G deletion syndrome II, on the othr hand, appear to be somewhat variable. We describe here the clinical and cytogenetic findings in a 13 year old male who has a deletion of the long arm of chromosome 22.