Left ventricular noncompaction cardiomyopathy:

Whole exome sequencing identifies novel candidate mutations in a Chinese family with left ventricular noncompaction

Left ventricular noncompaction (LVNC) is an inherited cardiomyopathy involving numerous genes. To identify novel candidate causal mutations, a whole exome sequencing study was performed on a Chinese LVNC family. Exons of the most prevalent pathogenic genes of LVNC (myosin heavy chain 7 and actin, α‑cardiac muscle 1) were sequenced, although no mutations were identified. Following this, Burrows‑Wheeler Aligner, PICARD and Genome Analysis Toolkit (v.2.8) were used to analyze the exome sequencing data. Non‑silent single nucleotide variants (SNVs) that were identified in patients with LVNC, although not in the healthy individual, were investigated further using SNV prioritization via the integration of genomic data (SPRING) based on P‑values. Co‑expressed gene enrichment analysis was performed using Genotype Tissue Expression (GTEx) data in order to investigate the potential roles of the genes containing SNVs in the myocardium. In the Chinese LVNC family, seven novel SNVs were identified that were only present in patients with LVNC and annotated by SPRING with P<0.05. Among these SNVs, hemicentin 1 [c. thymine (T) 9776 cytosine (C)], tolloid like 2 [c. cytosine (C) 2615 thymine (T)], fms related tyrosine kinase 3 [c. guanine (G) 976 adenine (A)] and nucleotide binding protein like [c. guanine (G) 91 thymine (T)] were located in conserved regions and annotated as deleterious by PolyPhen2, LRT and MutationTaster database analyses. Based on GTEx data, it was revealed that NUBPL was co‑expressed with almost all previously established LVNC pathogenic genes. Furthermore, the results of the present study demonstrated that genes co‑expressed with NUBPL were additionally enriched in the Notch signaling pathway. In addition, the results revealed numerous novel mutations that may be causal SNVs for the development of LVNC in the family involved in the present study.

Case report: Left ventricular noncompaction cardiomyopathy and RASopathies

The following is a case report of 6 patients with Noonan syndrome (NS) and/or a related RASsopathy that also have evidence of left ventricular noncompaction cardiomyopathy (LVNC). Noonan syndrome,a type of RASopathy, is an autosomal dominant disorder that is typically associated with congenital heart defects and hypertrophic cardiomyopathy. There have been minimal reports of Noonan syndrome or other RASopathy and the association of LVNC. This report promulgates 6 nonrelated cases of Noonan syndrome or unspecified RASopathy and LVNC.

Noncompaction Cardiomyopathy and Stroke: Case Report and Literature Review

BACKGROUND

To describe a rare case of isolated noncompaction cardiomyopathy and stroke and to review the medical literature on noncompaction cardiomyopathy.

METHODS

Retrospective chart review of the case was performed. Extensive literature review on etiology, clinical presentation, diagnosis, and management of noncompaction cardiomyopathy was also performed.

RESULTS

Our patient is a healthy 20-year-old woman who presented with sudden onset left face and arm weakness and hypesthesia. Magnetic resonance imaging (MRI) brain showed right middle cerebral artery (MCA) infarct. Magnetic resonance angiography head showed right MCA artery (M2) cutoff. MRI neck was nonsignificant. Echocardiogram was suggestive of noncompaction of left ventricle. Cardiac MRI confirmed the noncompaction of the left ventricle myocardium, which was thought to be the etiology of stroke. Patient was started on anticoagulation for secondary stroke prevention.

CONCLUSIONS

Isolated left ventricular noncompaction cardiomyopathy (LVNC) is a rare form of primary genetic cardiomyopathy, which occurs because of the arrest of the process of compaction of ventricular myocardium during embryogenesis. Noncompaction cardiomyopathy is usually associated with other primary cardiac structural abnormalities like dysfunctional cardiac valves. In isolated noncompaction cardiomyopathy, there are no other primary cardiac structural abnormalities. The most common clinical features seen in LVNC include left ventricular systolic dysfunction, congestive heart failure, arrhythmias, and cardiac embolic events theorized to result from thrombus formation within the intertrabecular recesses. As it is a rare disease, evidence-based recommendations for preventing thromboembolic events in isolated left ventricular noncompaction have not been established.