Shared Genetic Causes of Cardiac Hypertrophy in Children and Adults

Background The childhood onset of idiopathic cardiac hypertrophy that occurs without a family history of cardiomyopathy can portend a poor prognosis. Despite morphologic similarities to genetic cardiomyopathies of adulthood, the contribution of genetics to childhood-onset hypertrophy is unknown. Methods We assessed the family and medical histories of 84 children (63 boys and 21 girls) with idiopathic cardiac hypertrophy diagnosed before 15 years of age (mean [±SD] age, 6.99±6.12 years). We sequenced eight genes: MYH7, MYBPC3, TNNT2, TNNI3, TPM1, MYL3, MYL2,
and ACTC. These genes encode sarcomere proteins that, when mutated, cause adult-onset cardiomyopathies. We also sequenced PRKAG2 and LAMP2, which encode metabolic proteins; mutations in these genes can cause early-onset ventricular hypertrophy. Results We identified mutations in 25 of 51 affected children without family histories of cardiomyopathy and in 21 of 33 affected children with familial cardiomyopathy. Among 11 of the 25 children with presumed sporadic disease, 4 carried new mutations and 7 inherited the mutations. Mutations occurred predominantly (in >75% of the children) in MYH7 and MYBPC3; significantly more MYBPC3 missense mutations were detected than occur in adult-onset cardiomyopathy (P<0.005). p="0.007)">