Polymorphic trinucleotide repeat in the MEF2A gene at 15q26 is not expanded in familial cardiomyopathies.

A trinucleotide repeat polymorphism in the MEF2A gene is described. MEF2A is expressed early in cardiac muscle development; thus the possibility of linkage between this polymorphism and familial cardiomyopathies was investigated in three families not linked to genes coding for known sarcomeric proteins. MEF2A was excluded as a candidate for dilated cardiomyopathy (DCM)(LOD of -9.03) and hypertrophic cardiomyopathy (HCM)(LODs of -5.43 and -2.44) in these families. Because expansion of triplet repeats has been shown to be responsible for several inherited diseases, 121 unrelated HCM probands and 28 unrelated DCM probands were examined for evidence of expansion of this repeat. No expansion of this trinucleotide repeat was seen in any of the 149 cardiomyopathy probands.