Localization of the genetic locus for Saethre-Chotzen syndrome to a 6 cM region of chromosome 7 using four cases with apparently balanced translocations at 7p21.2.

Saethre-Chotzen syndrome is a common autosomal dominant form of craniosynostosis, which results in the premature fusion of cranial sutures. Craniosynostosis is commonly associated with abnormalities of 7p; Vortkamp et al. (Nature 352, 539-540) demonstrated that the GLI3 gene in 7p13 was disrupted in, patients with Greig syndrome and, more recently, the linkage of genetic markers from 7p with the Saethre-Chotzen syndrome locus has been reported (2,3). Here we report the analysis by fluorescence in situ hybridization of four patients with Saethre-Chotzen syndrome associated with apparently balanced translocations involving band 7p21.2 and different reciprocal chromosomes. We show that in all four patients the breakpoints in 7p are situated within a 6 cM region flanked by the genetic markers D7S488 and D7S493. These results provide further evidence that the genetic locus for Saethre-Chotzen syndrome is located in distal 7p.