The Bjornstad Syndrome (Sensorineural Hearing Loss and Pili Torti) Disease Gene Maps to Chromosome 2q34-36

Abstract

We report that the Bjornstad syndrome gene maps to chromosome 2q34-36. The clinical association of sensorineural hearing loss with pili torti (broken, twisted hairs) was described >30 years ago by Bjornstad; subsequently, several small families have been studied. We evaluated a large kindred with Bjornstad syndrome in which eight members inherited pili torti and prelingual sensorineural hearing loss as autosomal recessive traits. A genomewide search using polymorphic loci demonstrated linkage between the disease gene segregating in this kindred and D2S434 (maximum two-point LOD score = 4.98 at theta = 0). Haplotype analysis of recombination events located the disease gene in a 3-cM region between loci D2S1371 and D2S163. We speculate that intermediate filament and intermediate filament-associated proteins are good candidate genes for causing Bjornstad syndrome.