Exclusion of NFIL3 as the gene causing hereditary sensory neuropathy type I by mutation analysis

Hereditary sensory neuropathy type I (HSN-I) is an autosomal dominant perip heral neuropathy affecting sensory and motor neurons. The disease involves distal sensory loss, distal muscle wasting and weakness, and variable neura l deafness. The HSN1 locus has been mapped to a genetic interval of 3-4 cM on chromosome 9q22.1-q22.3 and is flanked by markers D9S1781 and FB19B7. Th is interval contains the gene NFIL3, a transcription factor that is regulat ed by the cytokine IL-3. Northern blot analysis of NFIL3 showed a ubiquitou sly expressed 2.2-kb mRNA. Expression was highest in the lung, with lower l evels of expression in the brain and spinal cord. Mutation analysis by dire ct sequencing of reverse transcription/polymerase chain reaction products f rom HSN-I patients excluded the coding region of the NFIL3 from being invol ved in the pathogenesis of HSN-I.