Localisation of the gene for Saethre-Chotzen syndrome by FISH using four cases with apparently balanced translocations at 7p21.2

Saethre-Chotzen is a common autosomal dominant form of craniosynostosis, which results in the premature fusion of cranial sutures. The Saethre-Chotzen gene locus has been mapped to 7p by linkage with genetic markers. We have analyzed four patients with Saethre-Chotzen syndrome associated with apparently balanced translocations involving band 7p21.2 and different reciprocal chromosomes. We have used YACs corresponding to the Genethon series of markers as probes for FISH, and in all four patients we show that the breakpoints in 7p are situated between D7S488 and D7S493, a maximum distance of 6 centimorgans. A previous patient has been described with a translocation t(6;7) and hemizygosity for D7S135. D7S135 is contained within the same YAC as D7S488, indicating that the breakpoint in the previous patient lies close to D7S488 and in the same region as the cases described here.