A YAC-based transcript map of human chromosome 9q22.1-q22.3 encompassing the loci for hereditary sensory neuropathy type I and multiple self-healing squamous epithelioma.

Hereditary sensory neuropathy type I (HSN-I) is an autosomal dominant peripheral neuropathy, involving sensory and motor neurons. The disease involves distal sensory loss, distal muscle wasting and weakness, and variable neural deafness. The HSN-I locus has been mapped to a 3- to 4-cM genetic interval on chromosome 9q22.1-q22.3. As part of a positional cloning effort to identify the HSN-I gene, we have generated a YAC based transcript map that spans approximately 8 Mb between D9S318 and D9S1786. This transcript map encompasses both the HSN-I critical interval and the locus for multiple self-healing squamous epithelioma (MSSE, previously named ESS1). Forty two ESTs and six characterized genes have been localized across 10 YAC clones, within a framework of 19 genetic linkage markers. Three other characterized genes were localized immediately adjacent to this interval. We have accurately mapped two recently identified genes: NINJ1 was anchored to D9S12II, and the localization of the NOR1 gene was significantly refined. We have also investigated NOR1 and several other characterized genes that localize to chromosome 9q22 for a pathogenic role in HSN-I. This map provides candidate genes for HSN-I and MSSE and is an important step toward completing a functional map of this gene-rich interval.