Phenotype and Functional Analyses in a Transgenic Mouse Model of Left Ventricular Noncompaction Caused by a DTNA Mutation

DTNA encoding dystrobrevin-α (α-DB) is a putative causal gene associated with left ventricular noncompaction cardiomyopathy (LVNC). The aim of the study was to investigate the causal role of DTNA in LVNC using a transgenic mouse model.A missense mutation (c.146A > G, p.N49S) of DTNA was identified in a patient with LVNC by Sanger Sequencing. Six independent lines of transgenic mice expressing the mutant DTNA under a Myosin heavy chain 6 (Myh6) promoter were generated (Myh6:Dtna^N49S). Phenotypic characteristics of DTNA-p.N49S mutations were evaluated by echocardiography, histological observation, and immunoblotting. Multiple trabeculation and a higher ratio of non-compacted to compact myocardial layer were found in the Myh6:Dtna^N49S mice compared to the controls. The transgenic mice also showed left ventricular (LV) dilation and cardiac systolic dysfunction. In conclusion, overexpression of the DTNA-p.N49S mutation in a mouse heart can be responsible for the phenotype of deep trabeculation, dilated cardiomyopathy, and cardiac dysfunction, which resembles the phenotype of LVNC.

Cardiomyopathy; Dystrobrevin-α; Sanger sequencing; Trabecular.