The genetics of hypertrophic cardiomyopathy

Abstract

Hypertrophic cardiomyopathy (HCM) is most commonly transmitted as an autosomal dominant trait, caused by mutations in genes encoding cardiac sarcomere proteins1–3. Other inheritable causes of the disease include mutations in genes coding for proteins important in calcium handling or that form part of the cytoskeleton4–6. At present, the primary clinical role of genetic testing in HCM is to facilitate familial screening to allow the identification of individuals at risk of developing the disease7,8. It is also used to diagnose genocopies, such as lysosomal9–11 and glycogen storage disease which have different treatment strategies, rates of disease progression and prognosis12–14. The role of genetic testing in predicting prognosis is limited at present, but emerging data suggest that knowledge of the genetic basis of disease will assume an important role in disease stratification15–17 and offer potential targets for disease-modifying therapy in the near future18.

Nanomechanical phenotypes in cMyBP-C mutants that cause hypertrophic cardiomyopathy

“…Despite encouraging advances 7 , currently there are no therapies to revert nor prevent HCM pathogenesis and clinical management relies on long-term palliative treatments and surgical procedures [4][5] . The majority of HCM cases are caused by autosomal dominant mutations targeting mechanical proteins of the sarcomere, the basic contractile unit of cardiomyocytes 5,[8][9] (Figure 1a). In sarcomeres, myosin heads use the energy coming from ATP hydrolysis to extend from the myosin backbone in the thick filaments, establish cross-bridges with the neighboring actin thin filaments and generate ~10-nm power strokes that propel the thin filaments past the thick ones leading to muscle contraction (Figure 1b) 4,8,[10][11][12] .…”

“…The majority of HCM cases are caused by autosomal dominant mutations targeting mechanical proteins of the sarcomere, the basic contractile unit of cardiomyocytes 5,[8][9] (Figure 1a). In sarcomeres, myosin heads use the energy coming from ATP hydrolysis to extend from the myosin backbone in the thick filaments, establish cross-bridges with the neighboring actin thin filaments and generate ~10-nm power strokes that propel the thin filaments past the thick ones leading to muscle contraction (Figure 1b) 4,8,[10][11][12] . Cardiac myosin-binding protein C (cMyBP-C) is a wellknown negative modulator of sarcomere contraction by complex mechanisms that are not fully understood [13][14][15] .…”

Echocardiography assessment of the left ventricle apical morphology and dynamics in patients with unexplainable deep T-wave inversion and apical wall thickness<15 mm

“…However, significant role of genetics is suggested in the pathogenesis of AHCM, which may well target the apical region. 15 From our results, we found mild or no change in the apical angles and velocity ratio in hypertensive control patients compared to healthy controls. Both AHCM and suspected AHCM groups however had significantly decreased apical angles and significantly increased apical flow velocity and velocity ratio.…”

Apical hypertrophic cardiomyopathy: diagnosis, medical and surgical treatment

“…The HCM is inherited in most cases in an autosomal dominant pattern, associated with over 1,500 known mutations in at least 15 genes encoding proteins of the sarcomere. Mutations in the genes encoding b-myosin heavy chain ( MYH7 ) and myosin-binding protein C3 ( MYBPC3 ) were found to be the most frequent cause of HCM, differing in sources from 50% to 70% [9, 10]. Other less frequent mutations known to cause HCM are found in genes encoding for troponin I ( TNNI3 ), troponin T ( TNNT2 ), and α-tropomyosin ( TPM1 ) [9].…”