Important insights into the etiology of osteoporosis have been gained by the study of single gene disorders, including osteogenesis imperfecta. We report on the genetic mapping of geroderma osteodysplastica (GO), a rare autosomal recessive disorder of the connective tissue, characterized by wrinkly skin and severe osteoporosis. We undertook autozygosity mapping in one Libyan and four consanguineous Pakistani families with a total of 10 affected individuals to define a 4 Mb homozygous region on chromosome 1q24, which harbors the GO causative gene. No obvious candidate genes that encode known protein constituents of the extracellular matrix are found in the linked region. Importantly, our study demonstrates that GO is not allelic to wrinkly skin syndrome caused by mutations in ATP6V0A2. © 2008 Wiley-Liss, Inc.