Novel RFLPs and microsatellite repeats increase informativity at four loci mapping to Xq22-q25.

Three microsatellites and five restriction fragment length polymorphisms (RFLPs) have been detected at loci DXS275, DXS97, DXS11 and DXS100. All of the reported polymorphisms are in linkage equilibrium with existing polymorphisms at these loci. However, two RFLPs at DXS275 and two at DXS97 appear to be in linkage disequilibrium with each other. Increased informativity at these loci have enabled exclusion of Xq22-q25 as a candidate region for X-linked spina bifida and anencephaly, and should aid in the mapping of other genes in the region.