Hypertrophic cardiomyopathy (HCM) is characterized by a hypertrophic, non-dilated left ventricle.With a prevalence of approximately 0.2% in humans and 15% in cats, this is one of the most commonheart diseases. The disorder is often inherited but may also be acquired during life. The clinicalsymptoms may differ. Genotypically affected individuals can exhibit (severe) symptoms of heartfailure or die suddenly, but they can also stay asymptomatic during their entire life.More than 1400 gene polymorphisms have already been detected in thirteen genes that code forsarcomere proteins in the heart in humans. Some of them are, together with modifying genes andenvironmental factors, responsible for the development of HCM. To date, only three mutations havebeen identified in cats. Commercial tests are already available to diagnose them. These mutations areresponsible for only a small fraction of the cases of HCM in cats. It is important to identify as manymutations as possible in order to develop a control strategy.There are a lot of common grounds between the human and feline forms of HCM. There aresimilarities in the mode of inheritance (autosomal), the clinical appearance and the histopathologicalchanges. Still, there is not enough known about sarcomere proteins and their mutations to extrapolateinformation from humans to cats and vice versa.