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Dilated cardiomyopathy and the dystrophin gene: an illustrated review
A Oldfors1, B O Eriksson, M Kyllerman
1Department of Pathology, Gothenburg University, Sahlgren Hospital, Sweden.
Insights
Dystrophin gene defects can cause severe heart conditions like dilated cardiomyopathy, even without significant muscle weakness. This highlights the importance of genetic testing for unexplained heart issues in young males.
Area of Science:
- Genetics
- Cardiology
- Neuromuscular Disorders
Background:
- Duchenne and Becker muscular dystrophies are X-linked disorders caused by dystrophin gene mutations.
- Cardiomyopathy is a common comorbidity in these muscular dystrophies.
- Dystrophin defects exhibit diverse clinical presentations, with varying severity of cardiac involvement.
Observation:
- Female carriers of Duchenne muscular dystrophy can present with skeletal myopathy and/or dilated cardiomyopathy.
- X-linked dilated cardiomyopathy is associated with dystrophin defects.
- The precise correlation between molecular dystrophin defects and cardiac phenotypes remains unclear.
Findings:
- New dystrophin gene mutations are frequent, accounting for one-third of Duchenne and Becker muscular dystrophy cases.
- Sporadic cases of cardiomyopathy linked to dystrophin defects are plausible.
- A 14-year-old boy with no prior muscle weakness complaints presented with limb girdle myopathy, elevated creatine kinase, and dilated cardiomyopathy due to an unusual dystrophin gene deletion.
Implications:
- This case underscores the potential for dystrophin gene mutations to cause cardiomyopathy as a primary manifestation.
- Genetic investigation of the dystrophin gene is crucial for diagnosing sporadic cases of dilated cardiomyopathy, particularly in young males.
- Further research is needed to elucidate the genotype-phenotype correlations in dystrophinopathies affecting the heart.
Abstract:
Cardiomyopathy is often found in patients with Duchenne and Becker muscular dystrophy, which are X linked muscle diseases caused by mutations in the dystrophin gene. Dystrophin defects present in many different ways and cases of mild Becker muscular dystrophy have been described in which cardiomyopathy was severe. Female carriers of Duchenne muscular dystrophy can develop symptomatic skeletal myopathy alone or combined with dilated cardiomyopathy. They can also develop dilated cardiomyopathy alone. X linked dilated cardiomyopathy has been found in association with dystrophin defects. The relation between the molecular defects and the cardiac phenotypes has not yet been established. New mutations in the dystrophin gene are common and such mutations cause one third of the cases with Duchenne and Becker muscular dystrophy. This means that sporadic cases of cardiomyopathy caused by dystrophin defects are likely. This paper reports such a case in a boy of 14 who died of dilated cardiomyopathy. Before the cardiac investigation, which was performed one month before he died, he had not complained of muscular weakness. He had minor signs of limb girdle myopathy and slightly increased concentrations of serum creatine kinase. He was found to have an unusual deletion in the dystrophin gene.