Twin studies in hypertrophic cardiomyopathy

Abstract

The details of three sets of twins, all with hypertrophic cardiomyopathy, are presented. Twins A were monozygotic and concordant and showed haemodynamic evidence of outflow tract obstruction. The lack of family history suggests a recessive mode of inheritance or a single gene mutation with dominant effect as the cause. Twins B were also monozygotic and concordant, but the rate of progression of their condition was different, one remaining well, the other developing atrial fibrillation and congestive cardiac failure. Twins C were dizygotic, the male member had died suddenly from hypertrophic cardiomyopathy as had his two young sons; the female member and her children are symptomless. The family history suggests a strongly penetrant autosomal dominant inheritance. Our observations suggest that hypertrophic cardiomyopathy could sometimes result from a single gene mutation and that the prenatal environment may be important in determining the expression of the gene and the rate of progression of the condition in adult life. The details of three sets of twins, all with hypertrophic cardiomyopathy, are presented. Twins A were monozygotic and concordant and showed haemodynamic evidence of outflow tract obstruction. The lack of family history suggests a recessive mode of inheritance or a single gene mutation with dominant effect as the cause. Twins B were also monozygotic and concordant, but the rate of progression of their condition was different, one remaining well, the other developing atrial fibrillation and congestive cardiac failure. Twins C were dizygotic, the male member had died suddenly from hypertrophic cardiomyopathy as had his two young sons; the female member and her children are symptomless. The family history suggests a strongly penetrant autosomal dominant inheritance. Our observations suggest that hypertrophic cardiomyopathy could sometimes result from a single gene mutation and that the prenatal environment may be important in determining the expression of the gene and the rate of progression of the condition in adult life.