RESUMEN
BACKGROUND: The rs7903146 and rs12255372 variants of TCF7L2 have been strongly associated with type 2 diabetes (T2D) risk in most populations studied to date. Meta-analysis of 27 different studies has resulted in a global OR of 1.46 [1.42-1.51] (rs7903146 variant). Thus far, despite a high incidence of T2D, the role of this variant in Arabs has not been established. METHODS: We performed a case-control association study using 522 Saudi T2D patients (WHO criteria), and 346 controls (age > 60; fasting plasma glucose < 7 mmol/L). Genotyping was performed by pyrosequencing. Statistical analyses were performed using SPSS version 13.0 for Windows (SPSS, Chicago, IL, USA). RESULTS: For rs7903146, the T allele frequency of the cases (0.415) was not different from that observed in the controls (0.405). The crude odds ratio (OR) was 1.04 with a 95% CI of 0.86-1.27 (P = 0.675). For rs12255372, the T allele frequency of the cases (0.368) was not different from that observed in the controls (0.355). Retrospective power calculations based upon an OR of 1.46 reported in a comprehensive meta-analysis of TCF7L2 risk, indicated this study was sufficiently powered (96.92%; alpha = 0.05) to detect an effect of similar magnitude to that reported for rs7903146. CONCLUSION: Our study is consistent with weak or no association of T2D in Arabs with the two TCF7L2 variants, however it cannot rule out an effect of other SNPs in this gene. Future studies in this population are required to confirm our findings and may indicate the presence of yet to be defined genetic risk factors for T2D.
Asunto(s)
Diabetes Mellitus Tipo 2/genética , Predisposición Genética a la Enfermedad , Factores de Transcripción TCF/genética , Anciano , Anciano de 80 o más Años , Alelos , Árabes , Estudios de Casos y Controles , Estudios de Cohortes , Femenino , Frecuencia de los Genes , Marcadores Genéticos , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Reacción en Cadena de la Polimerasa , Factores de Riesgo , Arabia Saudita , Análisis de Secuencia de ADN , Proteína 2 Similar al Factor de Transcripción 7RESUMEN
BACKGROUND: The E23K variant of KCNJ11 has been associated with type 2 diabetes (T2D) in several but not all populations studied. Thus far, despite a high incidence of T2D, the role of this variant in Arabs has not been established. METHODS: We performed a case-control association study using 550 T2D Saudi patients (WHO criteria), and 335 controls (age>or=60; fasting plasma glucose<7 mmol/L). E23K genotyping was performed by using molecular beacon-based real time PCR assays. RESULTS: The difference in K or risk allele frequency of cases and controls was significant with an OR of 1.7 (p=0.0001). The K allele is more common among T2D patients (21%) than in the age and sex matched controls (13.6%). This was consistent with a likely eventual conversion to T2D of younger normoglycemic individuals as they grow older. CONCLUSIONS: Our results report for the first time a positive association of the E23K variant with T2D in an Arab population. Confirmation by a larger study is indicated.