Autor: Prof.Adj. Dr. Hector Mario Musacchio

ABSTRACT:

Cardiomyopathies may have a genetic basis in about 20 percent of patients with dilated forms. And familial hypertrophic cardiomyopathy (FHC) is familial in aproximately 50% of cases.

X-linked muscular dystrophies are known to be caused by genetics alterations too.

These disorders can be calssified in two groups:

1- Disorders of cardiac energy and metabolism: includes alterations in fatty -acid oxidation and disorders of mitochondrial oxidative phosphorylation. 2- Abnormalities of myocardic contractile and structural proteins:
familial hypertrophic cardiomyopathy and X-linked muscular dystrophies.

Inborn Errors of Fatty-Acid Oxidation: apperas early in life and is

These defects are autosomal recesive disorders.

Disorders of Mitochondrial Oxidative Phosphorylation: These defects are due to mutations in the mitochondrial genome, and transmitted only from the maternal side.

Two types of mutation have been identified: point mutations and deletions.

Familial Hypertrophic Cardiomyopathy (FHC): is inherited as an autosomal dominant disease and has variable penetrance.

The mutation type cannot predict phenotypic expression, and spontaneus mutations occur frequently. Several mutations are in o near functional sites of the myosin molecule.

Three disease genes have been isolated and they encode cardiac sarcomeric proteins: beta-myosin heavy chain, troponin T and alpha-tropomyosin.

X-linked Muscular Dystrophy: in this disorder there is a prominent skeletal myopathy and cardiac involvement.

Duchenne and Becker muscular dystrophy are due to dystrophin gene abnormalities. Males are affected and females are carriers.

Conclusions: We should think in genetic causes even if there in no relatives affected (penetrance is variable). In this way we can define new diagnostic criteria and identify groups at highest risk for sudden death. It should be possible to adopt preventive mesures also.