Clinical and Prognostic Profiles of Cardiomyopathies Caused by Mutations in the Troponin T Gene.
OBJECTIVE
Mutations in the troponin T gene (TTNT2) have been associated in small studies with the development of hypertrophic cardiomyopathy characterized by a high risk of sudden death and mild hypertrophy. We describe the clinical course of patients carrying mutations in this gene.


METHODS
We analyzed the clinical characteristics and prognosis of patients with mutations in the TNNT2 gene who were seen in an inherited cardiac disease unit.


RESULTS
Of 180 families with genetically studied cardiomyopathies, 21 families (11.7%) were identified as having mutations in TNNT2: 10 families had Arg92Gln, 5 had Arg286His, 3 had Arg278Cys, 1 had Arg92Trp, 1 had Arg94His, and 1 had Ile221Thr. Thirty-three additional genetic carriers were identified through family assessment. The study included 54 genetic carriers: 56% were male, and the mean average age was 41 ± 17 years. There were 33 cases of hypertrophic cardiomyopathy, 9 of dilated cardiomyopathy, and 1 of noncompaction cardiomyopathy, and maximal myocardial thickness was 18.5 ± 6mm. Ventricular dysfunction was present in 30% of individuals and a history of sudden death in 62%. During follow-up, 4 patients died and 14 (33%) received a defibrillator (8 probands, 6 relatives). Mean survival was 54 years. Carriers of Arg92Gln had early disease development, high penetrance, a high risk of sudden death, a high rate of defibrillator implantation, and a high frequency of mixed phenotype.


CONCLUSIONS
Mutations in the TNNT2 gene were more common in this series than in previous studies. The clinical and prognostic profiles depended on the mutation present. Carriers of the Arg92Gln mutation developed hypertrophic or dilated cardiomyopathy and had a significantly worse prognosis than those with other mutations in TNNT2 or other sarcomeric genes.
Servicio de Cardiología, Hospital Son Llàtzer, IdISPa, Ciberobn, Palma de Mallorca, Balearic Islands, Spain. Electronic address: tripoll@hsll.es.
Tomás
T
Ripoll-Vera
Servicio de Cardiología, Hospital Son Llàtzer, IdISPa, Ciberobn, Palma de Mallorca, Balearic Islands, Spain.
José María
JM
Gámez
Sección de Genética, Hospital Son Espases, Palma de Mallorca, Balearic Islands, Spain.
Nancy
N
Govea
Servicio de Cardiología, Hospital Son Llàtzer, IdISPa, Ciberobn, Palma de Mallorca, Balearic Islands, Spain.
Yolanda
Y
Gómez
Servicio de Cardiología, Hospital Son Llàtzer, IdISPa, Ciberobn, Palma de Mallorca, Balearic Islands, Spain.
Juana
J
Núñez
Servicio de Cardiología, Hospital Son Llàtzer, IdISPa, Ciberobn, Palma de Mallorca, Balearic Islands, Spain.
Lorenzo
L
Socías
Servicio de Cardiología, Hospital Son Llàtzer, IdISPa, Ciberobn, Palma de Mallorca, Balearic Islands, Spain.
Ángela
Á
Escandell
Sección de Genética, Hospital Son Espases, Palma de Mallorca, Balearic Islands, Spain.
Jorge
J
Rosell
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002311:Cardiomyopathy, Dilated / Q000235:genetics* / Q000401:mortality; D002312:Cardiomyopathy, Hypertrophic / Q000235:genetics* / Q000401:mortality; D002648:Child; D016757:Death, Sudden, Cardiac / Q000209:etiology; D018572:Disease-Free Survival; D005260:Female; D018703:Founder Effect; D005838:Genotype; D006333:Heart Failure / Q000235:genetics; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation / Q000235:genetics*; D010375:Pedigree; D010641:Phenotype; D011379:Prognosis; D020107:Troponin T / Q000235:genetics*; D055815:Young Adult
C545568:TNNT2 protein, human; D020107:Troponin T
Cardiomyopathy; Genetic mutation; Genetics; Genética; Heart failure; Hipertrofia; Hypertrophy; Insuficiencia cardiaca; Miocardiopatía; Muerte súbita; Mutación génica; Sudden death; Troponin; Troponina