Nueva mutación fundadora en MYBPC3: comparación fenotípica con la mutación de MYBPC3 más frecuente en España / A novel founder mutation in MYBPC3: Phenotypic comparison with the most prevalent MYBPC3 mutation in Spain

Introducción y objetivos: Las mutaciones en MYBPC3 son causa de miocardiopatía hipertrófica (MCH). A pesar de que la mayoría de ellas producen una proteína truncada, la gravedad del fenotipo es diversa. Se describe el fenotipo clínico de una nueva mutación en MYBPC3, p.Pro108Alafs*9, presente en 13 familias del sur de España, y se compara con la mutación de MYBPC3 con mayor prevalencia en dicha región (c.2308 + 1 G > A). Métodos: Se estudió a 107 familiares de 13 casos índice que tenían diagnóstico de MCH y portaban la mutación p.Pro108Alafs*9. Se realizó un análisis del árbol genealógico, junto con una evaluación clínica y determinación del genotipo. Resultados: Se identificó en total a 54 portadores de la mutación p.Pro108Alafs*9, de los que 39 tenían MCH. Hubo 5 casos de muerte súbita en las 13 familias. La penetrancia de la enfermedad aumentaba a medida que se incrementaba la edad, y los pacientes con MCH fueron con más frecuencia varones, y estos contrajeron la enfermedad más precozmente que las mujeres. El fenotipo fue similar en la p.Pro108Alafs*9 y la c.2308 + 1 G > A, pero se observaron diferencias en varios factores de riesgo y en la supervivencia. Hubo tendencia a mayor masa ventricular izquierda en la p.Pro108Alafs*9 que en la c.2308 + 1G > A. La resonancia magnética cardiaca reveló una extensión y un patrón de fibrosis similares en ambas. Conclusiones: La mutación p.Pro108Alafs*9 se asoció a MCH, alta penetrancia y aparición de la enfermedad a mediana edad (AU)

Introduction and objectives: Mutations in MYBPC3 are the cause of hypertrophic cardiomyopathy (HCM). Although most lead to a truncating protein, the severity of the phenotype differs. We describe the clinical phenotype of a novel MYBPC3 mutation, p.Pro108Alafs*9, present in 13 families from southern Spain and compare it with the most prevalent MYBPC3 mutation in this region (c.2308 + 1 G > A). Methods: We studied 107 relatives of 13 index cases diagnosed as HCM carriers of the p.Pro108Alafs*9 mutation. Pedigree analysis, clinical evaluation, and genotyping were performed. Results: A total of 54 carriers of p.Pro108Alafs*9 were identified, of whom 39 had HCM. There were 5 cases of sudden death in the 13 families. Disease penetrance was greater as age increased and HCM patients were more frequently male and developed disease earlier than female patients. The phenotype was similar in p.Pro108Alafs*9 and in c.2308 + 1 G > A, but differences were found in several risk factors and in survival. There was a trend toward a higher left ventricular mass in p.Pro108Alafs*9 vs c.2308 + 1G > A. Cardiac magnetic resonance revealed a similar extent and pattern of fibrosis. Conclusions: The p.Pro108Alafs*9 mutation is associated with HCM, high penetrance, and disease onset in middle age (AU)

A Novel Founder Mutation in MYBPC3: Phenotypic Comparison With the Most Prevalent MYBPC3 Mutation in Spain.

INTRODUCTION AND OBJECTIVES: Mutations in MYBPC3 are the cause of hypertrophic cardiomyopathy (HCM). Although most lead to a truncating protein, the severity of the phenotype differs. We describe the clinical phenotype of a novel MYBPC3 mutation, p.Pro108Alafs*9, present in 13 families from southern Spain and compare it with the most prevalent MYBPC3 mutation in this region (c.2308+1 G>A). METHODS: We studied 107 relatives of 13 index cases diagnosed as HCM carriers of the p.Pro108Alafs*9 mutation. Pedigree analysis, clinical evaluation, and genotyping were performed. RESULTS: A total of 54 carriers of p.Pro108Alafs*9 were identified, of whom 39 had HCM. There were 5 cases of sudden death in the 13 families. Disease penetrance was greater as age increased and HCM patients were more frequently male and developed disease earlier than female patients. The phenotype was similar in p.Pro108Alafs*9 and in c.2308+1 G>A, but differences were found in several risk factors and in survival. There was a trend toward a higher left ventricular mass in p.Pro108Alafs*9 vs c.2308+1G>A. Cardiac magnetic resonance revealed a similar extent and pattern of fibrosis. CONCLUSIONS: The p.Pro108Alafs*9 mutation is associated with HCM, high penetrance, and disease onset in middle age.