[first paragraph of article]Hypertrophic cardiomyopathy is clinically defined by the presence of increased left ventricular (LV) wall thickness that is not solely explained by abnormal loading conditions. The aetiology is diverse, but in 60% of patients the disease is an autosomal dominant trait caused by cardiac sarcomere protein gene mutation (HCM). In 10% of cases, the cause is inherited metabolic and neuromuscular disease, chromosomic abnormalities and genetic syndromes, whereas, in the remaining 30% of patients the aetiology remains unknown.