Refined mapping of the Welander distal myopathy region on chromosome 2p13 positions the new candidate region telomeric of the DYSF locus

Welander distal myopathy (WDM) is a late adult-onset autosomal dominant disorder, characterized by a slow progression and distal limb weakness of the extremity muscles. The WDM locus has been mapped to chromosome 2p13. Within this region a common shared haplotype co-segregates in all affected patients, indicating a founder effect. By undertaking an extended linkage analysis we have significantly reduced the WDM locus to a critical interval of approximately 1.2 Mb flanked by markers D2S358 and PAC3-H52. The dysferlin gene, a strong candidate gene responsible for two other distal myopathies in the same region, is located centromeric to PAC3-H52 and can thereby formally be excluded as cause for WDM.