Novel α‐Actin Gene Mutation p.(Ala21Val) Causing Familial Hypertrophic Cardiomyopathy, Myocardial Noncompaction, and Transmural Crypts. Clinical‐Pathologic Correlation

Abstract

BackgroundMutations of α‐actin gene (ACTC1) have been phenotypically related to various cardiac anomalies, including hypertrophic cardiomyopathy and dilated cardiomyopathy and left ventricular (LV) myocardial noncompaction. A novel ACTC mutation is reported as cosegregating for familial hypertrophic cardiomyopathy and LV myocardial noncompaction with transmural crypts.Methods and ResultsIn an Italian family of 7 subjects, 4 aged 10 (II‐1), 14 (II‐2), 43 (I‐4) and 46 years (I‐5), presenting abnormal ECG changes, dyspnea and palpitation (II‐2, I‐4, and I‐5), and recurrent cerebral ischemic attack (I‐5), underwent 2‐dimensional echo, cardiac magnetic resonance, Holter monitoring, and next‐generation sequencing gene analysis. Patients II‐2 and I‐5 with ventricular tachycardia underwent a cardiac invasive study, including coronary with LV angiography and endomyocardial biopsy. In all the affected members, ECG showed right bundle branch block and left anterior hemiblock with age‐related prolongation of QRS duration. Two‐dimensional echo and cardiac magnetic resonance documented LV myocardial noncompaction in all and in I‐4, I‐5, and II‐2 a progressive LV hypertrophy up to 22‐mm maximal wall thickness. Coronary arteries were normal. LV angiography showed transmural crypts progressing to spongeous myocardial transformation with LV dilatation and dysfunction in the oldest subject. At histology and electron microscopy detachment of myocardiocytes were associated with cell and myofibrillar disarray and degradation of intercalated discs causing disanchorage of myofilaments to cell membrane. Next‐generation sequencing showed in affected members an unreported p.(Ala21Val) mutation of ACTC.ConclusionsNovel p.(Ala21Val) mutation of ACTC1 causes myofibrillar and intercalated disc alteration leading to familial hypertrophic cardiomyopathy and LV myocardial noncompaction with transmural crypts.

A new case of SMABF2 diagnosed in stillbirth expands the prenatal presentation and mutational spectrum of ASCC1

“…Enriched libraries were sequenced by a NextSeq500 instrument (Illumina, Inc.). Next‐generation‐sequencing (NGS) data were processed and analyzed using an in‐house implemented pipeline, as previously described (Frustaci et al, ). A total of 9,360 variants were found.…”

Heat shock proteins and small nucleolar RNAs are dysregulated in a Drosophila model for feline hypertrophic cardiomyopathy

“…Mutations in both these genes have been associated with familial HCM ( van Waning et al 2019 ; Manivannan et al 2020 ). Next-generation sequencing of an Italian family with HCM revealed an Ala21Val mutation in ACTC1 resulted in myofibrillar disarray causing dis-anchorage of myofilaments ( Frustaci et al 2018 ). These patients presented with palpitations and ventricular tachycardia due to structural defects of the myofilaments resulting from the Ala21Val mutation.…”

Whole-Exome Sequencing and hiPSC Cardiomyocyte Models Identify MYRIP, TRAPPC11, and SLC27A6 of Potential Importance to Left Ventricular Hypertrophy in an African Ancestry Population

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