INTERMEDIATE PHENOTYPE AND RISK OF DIABETIC NEPHROPATHY

描述：（改编自申请人摘要）强有力的证据表明，长期以来公认的30-40%的1型糖尿病（DM）患者具有肾病的特定风险，由于血糖控制和基因两个因素而具有这种风险。遗传因素似乎与高血压过程有关，因为它们与高血压家族史和红细胞Na:Li反运输增加有关。涉及肾素-血管紧张素系统（RAS）的几个基因已成为有吸引力的详细研究候选者，包括涉及血管紧张素原基因、ACE和AT1受体的多态性。一个主要的障碍，成功的遗传分析复杂的人类性状是他们的多因素决定，特别是病因异质性。因此，将远端表型作为二分类性状的唯一使用进展有限。增加病因同质性的一种有效方法是采用中间表型，这是一种生理或生化特征，可识别与感兴趣基因相关的特定患者亚群。中间表型也可以提供有关的生理机制的见解。本研究旨在确定这些上位性基因中一个或多个基因的多态性是否与血管紧张素介导的肾循环控制的改变有关，从而易患糖尿病肾病，并阐明基因、血糖控制和这些生理异常表达之间的相互作用。成功识别与特定遗传多态性相关的中间表型将为当前治疗提供见解，为识别特定风险患者提供新方法，并改进预防措施。

DESCRIPTION: (Adapted from the applicant's abstract) Strong evidence indicates that the long-recognized 30-40% of patients with type 1 diabetes mellitus (DM) who are at specific risk of nephropathy carry that risk because of two factors, glycemic control and genes. The genetic contributors appear to involve the hypertension process as they are associated with a strong family history of hypertension and increased red blood cell Na:Li countertransport. Several genes involving the renin-angiotensin system (RAS) have emerged as attractive candidates for detailed study, including polymorphism involving the angiotensinogen gene, ACE, and the AT1 receptor. A major barrier to successful genetic analysis of complex human traits is their multifactorial determination, specifically etiologic heterogeneity. Thus, the sole use of the distant phenotype as a dichotomous trait has limited progress. One powerful approach to increased etiologic homogeneity is to employ intermediate phenotypes, which are physiological or biochemical traits that identify specific subsets of patients for correlation with the gene of interest. The intermediate phenotype can also provide insight into the responsible physiological mechanisms. This study is designed to ascertain whether polymorphism in one or more of these genes in an epistatic relationship is associated with an alteration in angiotensin-mediated control of the renal circulation that predisposes to diabetic kidney disease, and to clarify the interaction between genes, glycemic control and expression of these physiologic abnormalities. Successful identification of intermediate phenotypes linked to specific genetic polymorphism would provide insight into current therapy, new approaches to identification of patients specifically at risk and improved preventative measures.