Cardiomyopathy, Dilated, 1jj

A number sign (#) is used with this entry because of evidence that dilated cardiomyopathy-1JJ (CMD1JJ) is caused by heterozygous mutation in the LAMA4 gene (600133) on chromosome 6q21.

For a general phenotypic description and a discussion of genetic heterogeneity of dilated cardiomyopathy, see CMD1A (115200).

Molecular Genetics

Knoll et al. (2007) sequenced the LAMA4 gene in 180 Caucasian patients with severe dilated cardiomyopathy (CMD) and identified heterozygosity for a nonsense (R1073X; 600133.0001) and a missense (P943L; 600133.0002) mutation in 2 patients, respectively. Genotyping for these mutations in an additional 374 Caucasian CMD patients identified 1 more patient with the P943L mutation. Neither mutation was found in 362 well-characterized Caucasian controls, and screening the LAMA4 gene by SSCP in an additional 200 Japanese CMD patients revealed no variants. Immunohistochemistry on myocardial biopsy samples revealed a significant loss of endothelial cells in the woman carrying the R1073X mutation, who had been diagnosed at 29 years of age and was a candidate for heart transplantation with an ejection fraction of only 20%. There was a more modest but still significant loss of endothelial cells in myocardial biopsies from the 2 men carrying the P943L mutation, who were diagnosed at ages 53 years and 68 years and had ejection fractions of 29% and 31%, respectively.