ClinVar

In affected members of 2 families with familial hypertrophic cardiomyopathy-10 (CMH10; 608758), Flavigny et al. (1998) identified a 173G-A transition in exon 4 of the MYL2 gene, resulting in an arg58-to-gln (R58Q) substitution. Affected individuals were classified morphologically as Maron type 1 or 3, and the mutation segregated with the hypertrophied phenotype in both families.

In a patient with asymmetric septal hypertrophic cardiomyopathy, Kabaeva et al. (2002) identified heterozygosity for the R58Q mutation. The patient had first been diagnosed at age 7 years with nonobstructive myocardial hypertrophy and underwent implantation of a cardioverter defibrillator at age 25 years after ventricular tachycardia degenerating into ventricular fibrillation was observed. She had recurrent episodes of supraventricular tachycardia, and echocardiography revealed asymmetric septal hypertrophy. DNA was not available from her sister, who had asymmetric obstructive myocardial hypertrophy and died suddenly at the age of 21 years, or from her father, who died unexpectedly at a young age and was found to have myocardial hypertrophy on autopsy. The mutation was not found in the proband's mother, who had normal cardiac findings.