Hypertrophic cardiomyopathy (HCM) is a genetic disorder that is characterized by left ventricular hypertrophy unexplained by secondary causes and a nondilated left ventricle with preserved or increased ejection fraction. It is commonly asymmetrical with the most severe hypertrophy involving the basal interventricular septum. Left ventricular outflow tract obstruction is present at rest in about one third of the patients and can be provoked in another third. The histological features of HCM include myocyte hypertrophy and disarray, as well as interstitial fibrosis. The hypertrophy is also frequently associated with left ventricular diastolic dysfunction. In the majority of patients, HCM has a relatively benign course. However, HCM is also an important cause of sudden cardiac death, particularly in adolescents and young adults. Nonsustained ventricular tachycardia, syncope, a family history of sudden cardiac death, and severe cardiac hypertrophy are major risk factors for sudden cardiac death. This complication can usually be averted by implantation of a cardioverter-defibrillator in appropriate high-risk patients. Atrial fibrillation is also a common complication and is not well tolerated. Mutations in over a dozen genes encoding sarcomere-associated proteins cause HCM. MYH7 and MYBPC3, encoding β-myosin heavy chain and myosin-binding protein C, respectively, are the 2 most common genes involved, together accounting for ≈50% of the HCM families. In ≈40% of HCM patients, the causal genes remain to be identified. Mutations in genes responsible for storage diseases also cause a phenotype resembling HCM (genocopy or phenocopy). The routine applications of genetic testing and preclinical identification of family members represents an important advance. The genetic discoveries have enhanced understanding of the molecular pathogenesis of HCM and have stimulated efforts designed to identify new therapeutic agents.

肥厚型心肌病（HCM）是一种遗传性疾病，其特征是继发性原因无法解释的左心室肥大和射血分数保持或增加的未扩张的左心室。它通常是不对称的，最严重的肥大涉及基底室间隔。约三分之一的患者在休息时存在左心室流出道梗阻，而另外三分之一的患者则可能引起左心室流出道梗阻。HCM的组织学特征包括肌细胞肥大和紊乱，以及间质纤维化。肥大也常与左心室舒张功能障碍有关。在大多数患者中，HCM的病程相对较温和。但是，HCM也是心脏骤然死亡的重要原因，尤其是在青少年中。不持续的室性心动过速，晕厥，心源性猝死家族史和严重的心脏肥大是心源性猝死的主要危险因素。通常可以通过在适当的高危患者中植入心脏复律除颤器来避免这种并发症。心房颤动也是常见的并发症，不能很好地耐受。编码肌节相关蛋白的十几个基因中的突变会导致HCM。分别编码β-肌球蛋白重链和肌球蛋白结合蛋白C的MYH7和MYBPC3是涉及的2个最常见的基因，合计占HCM家族的约50％。在约40％的HCM患者中，病因基因仍有待确定。导致贮藏病的基因突变也会引起类似于HCM的表型（基因型或表型）。基因检测和家庭成员临床前鉴定的常规应用代表了重要的进步。遗传发现增强了对HCM分子发病机理的了解，并刺激了旨在鉴定新治疗剂的努力。