SPLIT HAND SPLIT FOOT ANOMALY IN A FAMILY SEGREGATING A BALANCED TRANSLOCATION WITH BREAKPOINT ON 7Q22.1

An apparently balanced translocation, t(2;7)(q21.1;q22.1) was detected in a female patient with bilateral split hand and right split foot. S plit hand/split foot (SHSF) segregated as an autosomal dominant charac ter with low penetrance in her family. The translocation was present i n 6 of 13 additional relatives investigated, one of whom also had spli t hand on right. This observation provides further confirmation of the presence of a locus for SHSF on 7q and narrows the critical region to band 7q22.1. Defects caused by alterations of this chromosome region are variable and include manifestations of both syndromal and non-synd romal SHSF. Review of SHSF cases associated with chromosome 7 abnormal ities showed a preferential involvement of the lower limbs and of the right side, suggesting the action of locally restricted developmental resistance mechanisms. (C) 1993 Wiley-Liss, Inc.