Mutation of the MYH7 gene in a child with hypertrophic cardiomyopathy and Wolff-Parkinson-White syndrome

MYH7 in cardiomyopathy and skeletal muscle myopathy

Myosin heavy chain gene 7 (MYH7), a sarcomeric gene encoding the myosin heavy chain (myosin-7), has attracted considerable interest as a result of its fundamental functions in cardiac and skeletal muscle contraction and numerous nucleotide variations of MYH7 are closely related to cardiomyopathy and skeletal muscle myopathy. These disorders display significantly inter- and intra-familial variability, sometimes developing complex phenotypes, including both cardiomyopathy and skeletal myopathy. Here, we review the current understanding on MYH7 with the aim to better clarify how mutations in MYH7 affect the structure and physiologic function of sarcomere, thus resulting in cardiomyopathy and skeletal muscle myopathy. Importantly, the latest advances on diagnosis, research models in vivo and in vitro and therapy for precise clinical application have made great progress and have epoch-making significance. All the great advance is discussed here.

Wolff-Parkinson-White syndrome: De novo variants and evidence for mutational burden in genes associated with atrial fibrillation

BACKGROUND

Wolff-Parkinson-White (WPW) syndrome is a relatively common arrhythmia affecting ~1-3/1,000 individuals. Mutations in PRKAG2 have been described in rare patients in association with cardiomyopathy. However, the genetic basis of WPW in individuals with a structurally normal heart remains poorly understood. Sudden death due to atrial fibrillation (AF) can also occur in these individuals. Several studies have indicated that despite ablation of an accessory pathway, the risk of AF remains high in patients compared to general population.

METHODS

We applied exome sequencing in 305 subjects, including 65 trios, 80 singletons, and 6 multiple affected families. We used de novo analysis, candidate gene approach, and burden testing to explore the genetic contributions to WPW.

RESULTS

A heterozygous deleterious variant in PRKAG2 was identified in one subject, accounting for 0.6% (1/151) of the genetic basis of WPW in this study. Another individual with WPW and left ventricular hypertrophy carried a known pathogenic variant in MYH7. We found rare de novo variants in genes associated with arrhythmia and cardiomyopathy (ANK2, NEBL, PITX2, and PRDM16) in this cohort. There was an increased burden of rare deleterious variants (MAF ≤ 0.005) with CADD score ≥ 25 in genes linked to AF in cases compared to controls (P = .0023).

CONCLUSIONS

Our findings show an increased burden of rare deleterious variants in genes linked to AF in WPW syndrome, suggesting that genetic factors that determine the development of accessory pathways may be linked to an increased susceptibility of atrial muscle to AF in a subset of patients.

Aborted sudden cardiac death in a young soldier with concomitant hypertrophic cardiomyopathy and Wolff-Parkinson-White syndrome

We present a young soldier presenting with aborted sudden cardiac death, who was found to have concomitant hypertrophic cardiomyopathy and Wolff-Parkinson-White syndrome. Along with pathological haemodynamic features of hypertrophic cardiomyopathy, an easily-inducible re-entrant tachycardia was clearly documented in our patient. Given the fatal potential of supraventricular tachycardia in hypertrophic cardiomyopathy, we postulated that his tachyarrhythmia could potentially trigger the event. Upon his refusal to receive implantable cardioverter/defibrillator therapy, we ablated anatomical arrhythmogenic substrate instead, and he remained uneventfully over 3 years on β-blocker.

An Unusual Type of Localized Hypertrophic Cardiomyopathy With Wolf Parkinson White Syndrome Presenting With Pulmonary Edema

Hypertrophic cardiomyopathy (HCM) is an autosomal dominant heart disease that is the most common genetic cardiac disorder. The disease is characterized by excessive thickening of the left ventricular myocardium. The anterior portion of the interventricular ventricular septum is often involved. Asymmetric hypertrophy of apical site, left ventricular free wall, and right ventricle are less common in hypertrophic cardiomyopathy that occur in 1% cases. We report a case of a patient with an unusual type of hypertrophic cardiomyopathy and Wolf Parkinson White (WPW) presenting with pulmonary edema.

Clinical and genetic investigation of pediatric cases of Wolff-Parkinson-White syndrome in Tunisian families

BACKGROUND

Wolff-Parkinson-White (WPW) syndrome is an autosomal-dominant heart disease characterized by an accessory pathway that arises from an aberrant conduction from the atria to the ventricles. Several mutations within the PRKAG2 gene were shown to be responsible for WPW. This gene encodes the γ2 regulatory subunit of adenosine monophosphate (AMP)-activated protein kinase, which functions as a metabolic sensor in cells, responding to cellular energy demands.

METHODS

This first study of WPW in a North African population comprises the clinical and genetic investigation of 3 Tunisian families, including 11 affected members. The involvement of the PRKAG2 and NKX2-5 genes was investigated.

RESULTS

Mutation screening showed that with the exception of two already reported single-nucleotide polymorphisms, no mutations were detected within the coding region of PRKAG2 or in the NKX2-5 gene.

CONCLUSIONS

This study provides further evidence of the genetic heterogeneity of WPW.