A Case of Rare Inherited Restrictive Cardiomyopathy Caused by a Novel Mutation in Myh7 Gene

Abstract

Introduction: Inherited restrictive cardiomyopathy (RCM) is a rare cause of RCM associated with cytoskeletal and sarcoma gene mutations. We describe a case of inherited RCM due to MYH7s genetic mutation.Case description: A 66 year-old-woman was admitted for acute global heart failure. She had a family history of RCM with a mutation of MYH7 gene: sons sudden death at 30, one of her daughters who is 40 and grandson who is 1. The transthoracic cardiac ultrasound (TTE) showed a bi-atrial dilation, a non-dilated left ventricle (LV) non-hypertrophied. Genetic investigation found the same pathogenic missense mutation (c. 1477A>G in heterozygous state) in our patient and her daughter who has a non-obstructive hypertrophy cardiomyopathy (HCM).A few weeks later, our patient had a syncope on complete atrioventricular block. A triple chamber pace maker was installed. Discussion: Familial RCMs mutations are characterized by high allelic, genetic and phenotypic variability, with autosomal dominant inheritance and variable penetrance. This mutation is rarely found in RCM, it is usually reported in HCM (OMIM 160760). Genetic screening should be considered to identify patients at risk in families with suspected familial transmission. MYH7 mutations seem to be associated with severe phenotypes, earlier age of onset and more pejorative evolution than other mutations. Conclusion:The evaluation of familial RCM requires an understanding of its variable phenotypic expression and incomplete penetrance. RCM and HCM may coexist in the same family. Genetic testing for hereditary RCM should be considered when secondary causes have been excluded.