22q13 deletion syndrome

We have recently collected clinical information on 37 individuals with dele tion of 22q13 and compared the features of these individuals with 24 previo usly reported cases. The features most frequently associated with this dele tion are global developmental delay, generalized hypotonia, absent or sever ely delayed speech, and normal to advanced growth. Minor anomalies include dolicocephaly, abnormal ears, ptosis, dysplastic toenails, and relatively l arge hands, As with many terminal deletions involving pale G-band regions, the deletion can be extremely subtle and can go undetected on routine cytog enetic analysis. In fact, 32% of the individuals in our study had previous chromosome analyses that failed to detect the deletion. Eight of 37 individ uals had deletion of 22q13 secondary to an unbalanced chromosome translocat ion, In the newborn, this deletion should be considered in cases of hypoton ia for which other common causes have been excluded. In the older child, th is syndrome should be suspected in individuals with normal growth, profound developmental delay, absent or delayed speech, and minor dysmorphic featur es, We recommend high-resolution chromosome analysis and fluorescence in si tu hybridization studies, or molecular analysis to exclude this diagnosis. (C) 2001 Wiley-Liss, Inc.