Santos R.,Instituto Nacional Of Sade Ricardo Jorge |
Santos R.,University of Porto |
Oliveira J.,Instituto Nacional Of Sade Ricardo Jorge |
Vieira E.,Instituto Nacional Of Sade Ricardo Jorge |
And 10 more authors.
Journal of Human Genetics | Year: 2010
The allelic muscle disorders known as limb-girdle muscular dystrophy type 2B (LGMD2B), Miyoshi myopathy and distal anterior compartment myopathy result from defects in dysferlina sarcolemma-associated protein involved in membrane repair. Mutation screening in the dysferlin gene (DYSF) enabled the identification of seven Portuguese patients presenting the variant c.5492G > A, which was observed to promote skipping of exon 49 (p.Gly1802ValfsX17). Several residually expressed products of alternative splicing also involving exons 50 and 51 were detected in the leukocytes and muscle of both patients and normal controls. Quantitative transcript analysis confirmed these results and revealed that Δ49/Δ50 transcripts were predominant in blood. Although the patients were apparently unrelated, the c.5492GA mutation was found in linkage disequilibrium with a particularly rare haplotype in the population, corroborating the hypothesis of a common origin. Despite the presence of the same mutation on the same haplotype background, onset of the disease was heterogeneous, with either proximal or distal muscle involvement. © 2010 The Japan Society of Human Genetics. All rights reserved.