ArulJothi K N, Whitthall R A, Futema M, Humphries S E, George Melvin, Elangovan S, Nair Devaki R, Devi A
Department of Genetic Engineering, SRM University, Chennai, India.
Centre for Cardiovascular Genetics, Institute of Cardiovascular Science, University College London, London, UK.
Clin Biochem. 2016 Jun;49(9):669-674. doi: 10.1016/j.clinbiochem.2016.02.009. Epub 2016 Feb 27.
Cardiovascular disease is a leading cause of mortality in Indian population. Mutations in LDLR, APOB and PCSK9 genes may lead to Familial Hypercholesterolemia, an autosomal dominant disorder which in turn leads to cardiovascular diseases. The primary objective of this study is to analyze these genes in CAD patients of Indian population.
A total of 30 patients were selected out of 300 CAD patients based on UK-Simon Broome criteria from South India. The gDNA was isolated by organic extraction method and the exons and exon-intron boundaries of LDLR gene, APOB (exon 26) and PCSK9 (exon 7) were screened by PCR-high resolution melt analysis. The amplicons showing shift in melting pattern were sequenced to find out the variation.
This study reports three novel variations, an intronic deletion c.694+8_694+18del in intron 4, a synonymous variation c.966 C>T [p. (N322=)] in exon 7 and a deletion insertion c.1399_1340delinsTA [p. (T467Y)] in exon 10, two recurrent variations c.862G>A [p. (E288K)] in exon 6 and a splice site variation c.1845+2T>C in exon-intron junction of exon 12 in LDLR gene and PCSK9 gene had c.1180+17C>T change in intron 7. However there are no pathogenic variations in APOB and PCSK9 genes in Indian population. In silico analysis predicted all the variations as pathogenic except the synonymous variation.
This report adds five new variations to the spectrum of LDLR variations in Indian population. This study also suggests that UK Simon Broom criteria can be followed to categorize FH patients in Indian population.
心血管疾病是印度人群死亡的主要原因。低密度脂蛋白受体（LDLR）、载脂蛋白B（APOB）和前蛋白转化酶枯草溶菌素9（PCSK9）基因的突变可能导致家族性高胆固醇血症，这是一种常染色体显性疾病，进而导致心血管疾病。本研究的主要目的是分析印度人群冠心病（CAD）患者中的这些基因。
根据英国西蒙·布鲁姆标准，从印度南部的300例CAD患者中选出30例患者。通过有机提取法分离基因组DNA（gDNA），并通过聚合酶链反应-高分辨率熔解分析（PCR-HRM）筛查LDLR基因、APOB（第26外显子）和PCSK9（第7外显子）的外显子及外显子-内含子边界。对熔解模式出现变化的扩增子进行测序以找出变异情况。
本研究报告了三个新变异，一个是第4内含子的内含子缺失c.694+8_694+18del，一个是第7外显子的同义变异c.966 C>T [p. (N322=)]，还有一个是第10外显子的缺失插入c.1399_1340delinsTA [p. (T467Y)]；两个重复变异，分别是第6外显子的c.862G>A [p. (E288K)]以及LDLR基因第12外显子-内含子交界处的剪接位点变异c.1845+2T>C，PCSK9基因第7内含子有c.1180+17C>T变化。然而，印度人群的APOB和PCSK9基因中没有致病性变异。计算机模拟分析预测，除同义变异外，所有变异均为致病性变异。
本报告为印度人群LDLR变异谱增添了五个新变异。本研究还表明，在印度人群中可遵循英国西蒙·布鲁姆标准对家族性高胆固醇血症（FH）患者进行分类。
