Mutations in Sarcomere Protein Genes in Left Ventricular Noncompaction

• DOI: 10.1161/circulationaha.107.746164
• Publication Date: 2008-05-28T03:16:21Z
• Authors: Sabine Klaassen; Susanne Probst; Erwin Oechslin; Brenda Gerull; Gregor Krings; Pia Schuler; Matthias Greutmann; David Hürlimann; Mustafa Yegitbasi; Lucia Pons; Michael Gramlich; Jörg-Detlef Dren...; Arnd Heuser; Felix Berger; Rolf Jenni; Ludwig Thierfelder
• Keywords: Sarcomeres; Myosin Heavy Chains; Heart Ventricles; DNA Mutational Analysis; 610 Medicine & health; Heart; 2705 Cardiology and Cardiovascular Medicine; Actins; 3. Good health; Cohort Studies; 03 medical and health sciences; 2737 Physiology (medical); 0302 clinical medicine; Troponin T; Mutation; 10209 Clinic for Cardiology; Humans; Cardiomyopathies; Cardiac Myosins

Background—

Left ventricular noncompaction constitutes a primary cardiomyopathy characterized by a severely thickened, 2-layered myocardium, numerous prominent trabeculations, and deep intertrabecular recesses. The genetic basis of this cardiomyopathy is still largely unresolved. We speculated that mutations in sarcomere protein genes known to cause hypertrophic cardiomyopathy and dilated cardiomyopathy may be associated with left ventricular noncompaction.

Methods and Results—

Mutational analysis in a cohort of 63 unrelated adult probands with left ventricular noncompaction and no other congenital heart anomalies was performed by denaturing high-performance liquid chromatography analysis and direct DNA sequencing of 6 genes encoding sarcomere proteins. Heterozygous mutations were identified in 11 of 63 samples in genes encoding β-myosin heavy chain ( MYH7 ), α-cardiac actin ( ACTC ), and cardiac troponin T ( TNNT2 ). Nine distinct mutations, 7 of them in MYH7 , 1 in ACTC , and 1 in TNNT2 , were found. Clinical evaluations demonstrated familial disease in 6 of 11 probands with sarcomere gene mutations. MYH7 mutations segregated with the disease in 4 autosomal dominant LVNC kindreds. Six of the MYH7 mutations were novel, and 1 encodes a splice-site mutation, a relatively unique finding for MYH7 mutations. Modified residues in β-myosin heavy chain were located mainly within the ATP binding site.

Conclusions—

We conclude that left ventricular noncompaction is within the diverse spectrum of cardiac morphologies triggered by sarcomere protein gene defects. Our findings support the hypothesis that there is a shared molecular etiology of different cardiomyopathic phenotypes.