Perfil clínico y pronóstico de las miocardiopatías causadas por mutaciones en el gen de la troponina T / Clinical and prognostic profiles of cardiomyopathies caused by mutations in the troponin T gene

RESUMEN

Introducción y objetivos: Las mutaciones en el gen de la troponina T (TNNT2) se han asociado en pequeños estudios al desarrollo de miocardiopatía hipertrófica caracterizada por alto riesgo de muerte súbita e hipertrofia leve. Se describe el curso clínico de los pacientes portadores de mutaciones en este gen. Métodos: Se analizaron las características clínicas y el pronóstico de los sujetos con mutaciones en el gen TNNT2 atendidos en una unidad de cardiopatías familiares. Resultados: A partir de 180 familias con miocardiopatías estudiadas genéticamente, se identificó a 21 (11,7%) con mutaciones en TNNT2 10 familias Arg92Gln, 5 Arg286His, 3 Arg278Cys, 1 Arg92Trp, 1 Arg94His y 1 Ile221Thr. A través de la evaluación familiar se identificó a 33 portadores genéticos adicionales. El estudio incluyó a 54 portadores genéticos el 56% varones con una media de edad de 41 ± 17 años; 33 miocardiopatías hipertróficas, 9 dilatadas y 1 no compactada, con grosor máximo de 18,5 ± 6 mm; con disfunción ventricular el 30% y antecedentes de muerte súbita el 62%. En el seguimiento 4 fallecieron y 14 (33%) recibieron un desfibrilador (8 probandos, 6 familiares). La supervivencia media fue de 54 años. Los portadores de Arg92Gln tuvieron desarrollo precoz, alta penetrancia, alto riesgo de muerte súbita, alta tasa de implante de desfibrilador y alta frecuencia de fenotipo mixto. Conclusiones: Las mutaciones en el gen TNNT2 fueron más frecuentes en esta serie. Su perfil clínico y pronóstico depende de la mutación hallada. Los portadores de la mutación Arg92Gln desarrollaron miocardiopatía hipertrófica o dilatada y tuvieron un pronóstico significativamente peor que con otras mutaciones en TNNT2 u otros genes sarcoméricos (AU)

ABSTRACT

Introduction and aims: 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 theTNNT2 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 ± 6 mm. 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 (AU)