Two quantitative trait loci affecting progressive hearing loss in 101/H mice

Although recent progress in identifying genes involved in deafness has been remarkable, the genetic basis of progressive hearing loss (or age-related hearing loss) is poorly understood because of the extreme difficulty in studying such a late-onset, complex disease in human populations. Several inbred strains of mice such as 129P1/ReJ, C57BL/6J, DBA/2J, and BALB/cByJ have been reported to exhibit age-related hearing loss and provide valuable models for human nonsyndromic progressive deafness. In this article we show that 101/H mice also exhibit progressive deafness with early onset. Linkage analysis of F-2 populations derived from crosses between the 101/H and the MAI/Pas and MBT/Pas wild-derived mice suggested at least two major quantitative trait loci (QTLs) that influence progressive hearing loss. A first QTL, designated Phl1, was mapped with a maximum LOD score of 6.7 to the centromeric region of Chromosome 17, where no deafness-related QTL has been mapped so far. A second QTL, designated Phl2, mapped to Chromosome 10 and exhibited a maximum LOD score of 5.3. The map position of Phl2 near the well-known QTL of age-related hearing loss (Ahl) suggested the possibility of allelism, although the Ahl mutation itself did not segregate in these crosses. Finally, we found some evidence of epistatic interaction between Phl1 and Phl2.