Does delta-sarcoglycan-associated autosomal-dominant cardiomyopathy exist?

Area of Science:

• Genetics and Molecular Biology
• Neuromuscular Disorders
• Cardiovascular Genetics

Background:

• The delta-sarcoglycan gene is implicated in muscular dystrophies and cardiomyopathies.
• Autosomal-dominant dilated cardiomyopathy is a severe condition often linked to genetic factors.
• Understanding genotype-phenotype correlations is crucial for genetic disease diagnosis.

Purpose of the Study:

• To investigate the clinical and genetic effects of a novel homozygous delta-sarcoglycan mutation.
• To evaluate the pathogenicity of a previously reported delta-sarcoglycan variant (p.S151A) in compound heterozygotes.
• To clarify the role of delta-sarcoglycan in autosomal-dominant dilated cardiomyopathy.

Main Methods:

• Clinical assessment of a consanguineous family.
• Genetic sequencing to identify mutations in the delta-sarcoglycan gene.
• Comprehensive cardiac investigations in affected and carrier family members.

Main Results:

• A novel homozygous missense mutation (p.A131P) in the delta-sarcoglycan gene caused limb girdle muscular dystrophy.
• Compound heterozygotes carrying both p.A131P and the previously reported p.S151A variant showed no signs of cardiomyopathy or muscular dystrophy.
• The p.S151A variant did not lead to cardiomyopathy in compound heterozygous individuals.

Conclusions:

• Homozygosity for the novel delta-sarcoglycan p.A131P mutation results in limb girdle muscular dystrophy.
• The delta-sarcoglycan p.S151A variant may not be pathogenic for autosomal-dominant dilated cardiomyopathy, even when present with another disease-causing mutation.
• This study challenges the established role of the delta-sarcoglycan gene in autosomal-dominant dilated cardiomyopathy.