RESUMEN
BACKGROUND: Hypertrophic cardiomyopathy is a genetic autosomal dominant disease characterized by left ventricular hypertrophy. The molecular diagnosis is important but still expensive. This work aimed to find clinical predictors of a positive genetic test in a Brazilian tertiary centre cohort of index cases with HCM. METHODS: In the study were included patients with HCM clinical diagnosis. For genotype x phenotype comparison we have evaluated echocardiographic, electrocardiographic, and nuclear magnetic resonance measures. All patients answered a questionnaire about familial history of HCM and/or sudden death. ß-myosin heavy chain, myosin binding protein C, and troponin T genes were sequenced for genetic diagnosis. RESULTS: The variables related to a higher probability of a positive genetic test were familial history of HCM, higher mean heart frequency, presence of NSVT and lower age. Probabilities of having a positive molecular genetic test were calculated from the final multivariate logistic regression model and were used to identify those with a higher probability of a positive molecular diagnosis. CONCLUSIONS: We developed an easy and fast screening method that takes into account only clinical data that can help to select the patients with a high probability of positive genetic results from molecular sequencing of Brazilian HCM patients.
Asunto(s)
Cardiomiopatía Hipertrófica Familiar/genética , Análisis Mutacional de ADN , Pruebas Genéticas/métodos , Mutación , Adolescente , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Brasil , Cardiomiopatía Hipertrófica Familiar/diagnóstico , Cardiomiopatía Hipertrófica Familiar/fisiopatología , Femenino , Predisposición Genética a la Enfermedad , Frecuencia Cardíaca , Humanos , Modelos Logísticos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Linaje , Fenotipo , Valor Predictivo de las Pruebas , Factores de Riesgo , Encuestas y Cuestionarios , Taquicardia Ventricular/genética , Taquicardia Ventricular/fisiopatología , Centros de Atención Terciaria , Adulto JovenRESUMEN
BACKGROUND: Hypertrophic cardiomyopathy (HC) is the most prevalent genetic cardiac disease caused by a mutation in sarcomeres, Z-disks, or calcium-handling genes and is characterized by unexplained left ventricular hypertrophy. The aim of this study was to determine the genetic profile of Brazilian patients with HC and correlate the genotype with the phenotype. METHODS: We included 268 index patients from São Paulo city and 3 other cities in Brazil and extracted their DNA from whole blood. We amplified the coding sequencing of MYH7, MYBPC3, and TNNT2 genes and sequenced them with an automatic sequencer. RESULTS: We identified causal mutations in 131 patients (48.8%). Seventy-eight (59.5%) were in the MYH7 gene, 50 (38.2%) in the MYBPC3 gene, and 3 (2.3%) in the TNNT2 gene. We identified 69 mutations, 24 not previously described. Patients with an identified mutation were younger at diagnosis and at current age, had a higher mean heart rate and higher nonsustained ventricular tachycardia frequency compared with those without a mutation. Patients with MYH7 gene mutations had a larger left atrium and higher frequency of atrial fibrillation than did patients with MYBPC3 gene mutations. CONCLUSION: The presence of a mutation in one of the genes suggests a worse prognosis. Mutations in the MYH7 gene, rather than in the MYBPC3 gene, were also related to a worse prognosis. This is the first work characterizing HC molecular epidemiology in the Brazilian population for the 3 most important genes.
