title: A novel mutation Lys273Glu in the cardiac troponin T gene shows high degree of penetrance and transition from hypertrophic to dilated cardiomyopathy.
abstract: Familial hypertrophic cardiomyopathy (HC) can be caused by mutations in 9 different genes encoding sarcomere proteins expressed in cardiac muscle. To date, only 13 different mutations in the cardiac troponin T (cTnT) gene have been reported to cause HC. Clinical characteristics and prognosis associated with mutations of this gene have not been well characterized owing to the small size and composition of affected families. The aim of this study was to determine the characteristic phenotype of patients with HC caused by a novel cTnT gene mutation, Lys273Glu. Two hundred Japanese probands with HC were screened for mutations in the cTnT gene. The Lys273Glu missense mutation was present in 9 persons from 2 unrelated pedigrees. They exhibited different cardiac morphologies: 1 had a dilated cardiomyopathy-like feature, 7 had left ventricular hypertrophy with normal left ventricular systolic function, and the 6 of them had asymmetric septal hypertrophy. A 1-year-old boy was not evaluated with echocardiography. The mean maximum wall thickness was 18.0 +/- 5.5 mm (range 8 to 24). There were 7 histories of sudden death in 1 of the 2 families. The Lys273Glu substitution in the cTnT gene shows a high degree of penetrance (100% in persons aged >20 years), a high incidence of sudden death, and a partial transition from hypertrophic to dilated cardiomyopathy. Because the location of a mutation appears to influence the development of a phenotype, we suggest that the precise definition of the disease-causing mutation can provide important prognostic information about affected members.
authors.affiliation: The Second Department of Internal Medicine, School of Medicine, Kanazawa University, Kanazawa, Japan.
authors.forename: Noboru
authors.initials: N
authors.lastname: Fujino
authors.forename: Masami
authors.initials: M
authors.lastname: Shimizu
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Ino
authors.forename: Masato
authors.initials: M
authors.lastname: Yamaguchi
authors.forename: Toshihiko
authors.initials: T
authors.lastname: Yasuda
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Nagata
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Konno
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Mabuchi
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D044466:Asian People / Q000235:genetics; D002311:Cardiomyopathy, Dilated / Q000235:genetics*; D024741:Cardiomyopathy, Hypertrophic, Familial / Q000235:genetics*; D002648:Child; D002675:Child, Preschool; D018450:Disease Progression; D004452:Echocardiography; D005260:Female; D006801:Humans; D007223:Infant; D007564:Japan; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010375:Pedigree; D011379:Prognosis; D020107:Troponin T / Q000235:genetics*
chemical_list: D020107:Troponin T