Novel five nucleotide deletion in dysferlin leads to autosomal recessive limb-girdle muscular dystrophy

Abstract

Muscular dystrophy (MD) is a genetic disorder that causes progressive muscle weakness and degeneration. Limb-girdle muscular dystrophy (LGMD) is a type of MD that mainly causes muscle atrophy within the shoulder and pelvic girdles. LGMD is classified into autosomal dominant (LGMD-D) and autosomal recessive (LGMD-R) inheritance patterns. Mutations in the Dysferlin gene (DYSF) are common causes of LGMD-R. However, genetic screening of DYSF mutations is rare in Taiwan. Herein, we identified a novel c.2867_2871del ACCAG deletion and a previously reported c.937+1G>A mutation in DYSF from a Taiwanese family with LGMD. The primary symptoms of both siblings were difficulty climbing stairs, walking on the toes, and gradually worsening weakness in the proximal muscles and increased creatine kinase level. Through pedigree analysis and sequencing, two siblings from this family were found to have compound heterozygous DYSF mutations (c. 937+1G>A and c. 2867_2871del ACCAG) within the separated alleles. These mutations induced early stop codons; if translated, truncated DYSF proteins will be expressed. Or, the mRNA products of these two mutations will merit the nonsense-mediated decay, might result in no dysferlin protein expressed. To our knowledge, this is the first report of a novel c.2867_2871del ACCAG deletion in DYSF. Further research is required to examine the effects of the novel DYSF mutation in Taiwanese patients with LGMD.

Keywords: dysferlin; heterozygous mutation; limb-girdle muscular dystrophy.