DNA variation in myoMIRs of the 1, 133, and 208 families in hypertrophic cardiomyopathy

MicroRNAs (miRNAs) are small RNAs that bind to mRNAs and regulate gene expression. MyoMirs are miRNAs implicated in cardiogenesis. Some MyoMirs have been found deregulated in hearts from patients with left ventricular hypertrophy (LVH). DNA variants at these miRNAs could contribute to the risk of developing hypertrophic cardiomyopathy (HCM). To test this hypothesis we used single strand conformation analysis and direct sequencing to search for DNA variants in the mir-208a, miR-208b, miR-133a-1, miR-133a-2, miR-133b, miR-1-1, and miR-1-2 genes in patients with HCM (n=245), LVH secondary to hypertension (n=120), and healthy controls (n=250). We found several nucleotide variants. Genotyping of patients and healthy controls showed significantly associations between a 133a-1 polymorphism and HCM and a 133b polymorphism and hypertensive- LVH. We concluded that rare variants in these mature miRNAs would be rarely found among HCM patients, but miR-133a-1 and 133b polymorphisms could contribute to the risk of developing cardiac hypertrophy.