Discerning the genetic contributors to autonomous aldosterone production through whole genome sequencing

与世界其他地区一样，马来西亚的高血压（高血压）患病率很高，18岁以上的人占32.7%。难以控制的高血压可能导致合并症和死亡，因为它是中风和心脏病的主要危险因素。原发性醛固酮增多症（PA），表现为肾上腺分泌过多的醛固酮激素，可能是高血压最常见的可治愈的原因。虽然最近的一份报告表明，60%的高血压患者患有PA，但更保守的估计是，集中在可治愈的患者中，可能占所有患者的5-10%，但在难治性高血压患者和低肾素高血压种族群体中的比例要高得多。在许多患者中，单侧肾上腺醛固酮腺瘤（阿帕）的发现为完全治愈高血压提供了机会。然而，像马来西亚这样的发展中国家缺乏识别这些患者的资源。目前，即使对PA进行可靠的诊断也是令人担忧的，需要从高危患者中停用大多数一线抗高血压药物以进行激素（肾素和醛固酮）测量，如果需要进行确证性试验（例如生理盐水或卡托普利抑制），则通常不止一次。因此，目前只有不到1%的PA患者被诊断出来。然而，防止过量的醛固酮不仅对减轻可导致心血管疾病的高血压至关重要，而且对防止直接的心脏损害也至关重要。因此，我们的目标是在这个建议，以确定自主醛固酮生产的遗传贡献者，使用强大的全基因组测序技术，希望开发一种低成本的高通量外周血检测，将允许大规模诊断和自主醛固酮生产的靶向治疗。全基因组测序是一种检测个体所有基因序列的强大技术，将能够识别与PA相关的遗传突变。据估计，遗传对血压个体间变异的贡献率为25-64%，但目前全基因组关联研究仅确定了约3.5%的遗传贡献，大多数命中发生在非编码区。这项工作将提供疾病发展的更深层次的遗传学理解，特别是在非基因编码调控序列和遗传性生殖系突变和发生在肾上腺的体细胞突变之间的相互作用。有趣的是，在最近发布的英国生物库数据中，与PA相关的最热门GWAS多态性之一是SMUG 1，这是一种DNA修复基因，其失败的标志是C/T或G/A突变。值得注意的是，PA患者中几乎一半的醛固酮产生细胞簇和微醛固酮产生腺瘤具有这种特征。我们假设WGS将发现信息性的因果变异，例如在增强子区域，这在对照人群数据库中是罕见的（<1%），但在记录的PA中，醛固酮驱动基因的体细胞突变的频率要高出10倍。这样的发现可能会得到临床上有用的诊断测试的潜力的奖励，这是一个潜力，这是从来没有实现的常见SNP在GWAS中使用。我们推测，低肾素高血压是由于未确诊的自主醛固酮生产和低技术高通量检测，可以从这项研究中开发将降低诊断成本，并证明廉价的预防性治疗，尽管螺内酯的已知过多的副作用。利用该项目产生的新信息，可以开发一种简单的基因分型测试来识别由于自主醛固酮产生的高血压患者，然后可以通过廉价的醛固酮受体拮抗剂螺内酯治疗，降低血压和心血管疾病的风险。

Malaysia, like the rest of the world, has a high prevalence of high blood pressure (hypertension), 32.7% for aged >18 years. Difficult to control hypertension can lead to co-morbidities and mortality as it is a major risk factor for stroke and heart diseases. Primary aldosteronism (PA), showing excess production of the hormone aldosterone from the adrenal glands, is probably the commonest curable cause of hypertension. While a recent report suggested that 60% of patients with hypertension have PA, a more conservative estimate, with concentration on curable patients, might suggest 5-10% of all patients, but in much higher proportions among those with treatment resistant hypertension, and ethnic groups with low-renin hypertension. In many patients, the discovery of a unilateral aldosterone-producing adenoma (APA) of the adrenal gland offers the opportunity for complete cure of hypertension. However developing country like Malaysia lacks the resources to identify these patients. Even making a reliable diagnosis of PA is currently fraught, requiring withdrawal of most first-line antihypertensive drugs from high-risk patients for the hormone (renin and aldosterone) measurements, often on more than one occasion if a confirmatory test (e.g saline or captopril suppression) is required. Hence, <1% of patients with PA are currently diagnosed. However, preventing excessive aldosterone is not only essential to attenuate high blood pressure which can lead to cardiovascular diseases, but also to prevent direct cardiac damage. We therefore aim in this proposal to identify the genetic contributors for autonomous aldosterone production, using the powerful whole genome sequencing technology, with the hope of developing a low-cost high-throughput peripheral blood assay that will allow mass diagnosis and targeted treatment of autonomous aldosterone production. Whole genome sequencing, a powerful technology to detect all the genetic sequences in an individual, will be able to identify heritable mutations associated with PA. Heredity is estimated to contribute 25-64% of inter-individual variation in blood pressure, yet currently genome-wide association studies have only identified ~3.5% of the genetic contribution with most hits occurring in the non-coding regions. This work will provide deeper genetic understanding of the disease development especially on the non gene-coding regulatory sequences and interplay between heritable germline mutations and somatic mutations that occur in the adrenal. Interestingly, one of the top hit GWAS polymorphism associated with PA in the recently released UK Biobank data is SMUG1, a DNA repair gene where the signature for its failure is C/T or G/A mutations. To note, almost half of aldosterone-producing cell clusters and micro-aldosterone-producing adenomas in PA patients have this signature. We hypothesize that WGS will discover informative, causal variants, e.g. in enhancer regions, which are rare (<1%) in control population databases, but >10-fold more frequent in documented PA with somatic mutation in aldosterone-driver genes. Such discovery may be rewarded by the potential for a clinically useful diagnostic test, a potential which is never realised by the common SNPs used in GWAS. We postulate that much of low-renin hypertension is due to undiagnosed autonomous aldosterone production and the low tech high throughput assay that can be developed from this study will cut cost of diagnosis and justify cheap preventive treatment despite spironolactone's known plethora of side effects. With the new information generated from this project, a simple genotyping test may be developed to identify hypertensive patients due to autonomous aldosterone production, which can then be treated by the cheap aldosterone receptor antagonist spironolactone, decreasing blood pressure and risk of cardiovascular diseases.