Cardiac diseases as a predictor warning of hereditary muscle diseases. The case of laminopathies

Mutations in the LMNA gene are associated with a wide spectrum of disease phenotypes, ranging from neuromuscular, cardiac and metabolic disorders to premature aging syndromes. Skeletal muscle involvement may present with different phenotypes: limb-girdle muscular dystrophy type 1B or LMNA-related dystrophy; autosomal dominant Emery-Dreifuss muscular dystrophy; and a congenital form of muscular dystrophy, frequently associated with early onset of arrhythmias. Heart involvement may occur as part of the muscle involvement or independently, regardless of the presence of the myopathy. Notably conduction defects and dilated cardiomyopathy may exist without a muscle disease. This paper will focus on cardiac diseases presenting as the first manifestation of skeletal muscle hereditary disorders such as laminopathies, inspired by two large families with cardiovascular problems long followed by conventional cardiologists who did not suspect a genetic muscle disorder underlying these events. Furthermore it underlines the need for a multidisciplinary approach in these disorders and how the figure of the cardio-myo-geneticist may play a key role in facilitating the diagnostic process, and addressing the adoption of appropriate prevention measures.