Using microsatellite markers developed as part of the genetic mapping program of the Human Genome Project, the map locations of several disease genes were elucidated. These include the loci for cerebral cavernous angiomas on 7q, the gene for cystinosis on 17pter, the gene for the Ellis van Creveld syndrome on 4p16, the gene for pyknodysostosis on 1q21, and the gene for synpolydactyly on 2q. We have also continued our efforts in genetic and physical mapping of the region harboring the Wolfram syndrome susceptibility gene, and we are presently examining candidate genes from the region.