Long-term outcome of 4 Korean families with hypertrophic cardiomyopathy caused by 4 different mutations.

BACKGROUND

We sought to describe the long-term outcome of individuals in 4 Korean families with hypertrophic cardiomyopathy (HCM) with known mutations.

HYPOTHESIS

Long-term clinical features of familial HCM might be characterized according to the mutation causing HCM.

METHODS

We performed long-term (mean, 13.1 y) clinical evaluations on 46 subjects from 4 Korean families with different mutations.

RESULTS

Myosin light chain 3 gene (MYL3) mutation was associated with late-onset HCM with relatively poor prognosis; 1 sudden cardiac death and 2 cases of heart failure with atrial fibrillation occurred among 12 subjects with this mutation. Myosin binding protein C gene (MYBPC3) mutation was associated with 2 cases of sudden cardiac death and 3 cases of heart failure among 7 affected members. Cardiac troponin I type 3 gene (TNNI3) mutation was associated with 5 deaths related to atrial fibrillation and stroke among 12 mutation-positive members. Myosin heavy chain 7 gene (MYH7) mutation was associated with 11 deaths in 15 affected members.

CONCLUSIONS

The clinical course was quite different for different HCM mutations. Even within the same family, individuals carrying the same mutation differed in disease expression and prognosis.