Characterization of a 16 Mb interstitial chromosome 7q21 deletion by tiling path array CGH

We report on a 42‐year‐old female patient with an interstitial 16 Mb deletion in 7q21.1‐21.3 and a balanced reciprocal translocation between chromosomes 6 and 7 [karyotype 46,XX,t(6;7)(q23.3;q32.3)del(7)(q21.1q21.3)de novo]. We characterized the size and position of the deletion by tiling path array comparative genomic hybridization (CGH), and we mapped the translocation breakpoints on chromosomes 6 and 7 by FISH. The clinical features of this patient—severe mental retardation, short stature, microcephaly and deafness—are in accordance with previously reported patients with 7q21 deletions. Chromosome band 7q21.3 harbors a locus for split hand/split foot malformation (SHFM1), and part of this locus, including the SHFM1 candidate genes SHFM1 , DLX5 , and DLX6 , is deleted. The absence of limb abnormalities in this patient suggests either a location of the SHFM1 causing factor distal to this deletion, or reduced penetrance of haploinsufficiency of a SHFM1 factor within the deleted interval. © 2007 Wiley‐Liss, Inc.