A first missense mutation in the δ sarcoglycan gene associated with a severe phenotype and frequency of limb-girdle muscular dystrophy type 2F (LGMD2F) in Brazilian sarcoglycanopathies

Abstract

Among the heterogeneous group of autosomal recessive limb-girdle muscular dystrophies (AR LGMDs), the sarcoglycanopathies (LGMD2C-2F) represent a subgroup characterised by defects in the γ, α, β, and δ sarcoglycan genes, respectively. Genotype-phenotype correlations in these forms of AR LGMD are important to enhance our understanding of protein function. Regarding LGMD2F, only two homozygous frameshift mutations have been reported to date in patients with a severe phenotype. In the present report, through screening 23 unrelated AR LGMD patients, we identified three subjects with LGMD2F, two with a previously reported frameshift mutation and the other homozygous for a new missense mutation in the δ sarcoglycan gene. Interestingly, this new mutation is also associated with a severe clinical course. In addition, our results suggest that this form of severe AR LGMD is not very rare in our population.