MYO1F as a candidate gene for nonsyndromic deafness, DFNB15

Background: Earlier studies have mapped the autosomal recessive nonsyndromi c deafness locus, DFNB15, to chromosomes 3q21.3-q25.2 and 19p13.3-13.1, ide ntifying one of these chromosomal regions (or possibly both) as the site of a deafness-causing gene. Mutations in unconventional myosins cause deafnes s in mice and humans. One unconventional myosin, myosin 1F (MYO1F), is expr essed in the cochlea and maps to chromosome 19p13.3-13.2. Objective: To evaluate MYO1F as a candidate gene for deafness at the DFNB15 locus by determining its genomic structure and screening each exon for dea fness-causing mutations to identify possible allele variants of MYO1F segre gating in the DFNB15 family. Methods: We used radiation hybrid mapping to localize MYO1F on chromosome a rm 19p. We next determined its genomic structure using multiple long-range polymerase chain reaction experiments. Using these data, we completed mutat ion screening using single-stranded conformational polymorphism analysis an d direct sequencing of affected and nonaffected persons in the original DFN B15 family. Results: Radiation hybrid mapping placed MYO1F in the DFNB15 interval, esta blishing it as a positional candidate gene. Its genomic structure consists of 24 coding exons. No mutations or genomic rearrangements were found in th e original DFNB15 family, making it unlikely that MYO1F is the disease-caus ing gene in this kindred. Conclusions: Although we did not find MYO1F allele variants in one family w ith autosomal recessive nonsyndromic hearing loss, the gene remains an exce llent candidate for hereditary hearing impairment. Given its wide tissue ex pression, MYO1F might cause syndromic deafness.