Das Bhowmik Aneek, Dalal Ashwin, Matta Divya, Kandadai Rukmini M, Kanikannan Meena A, Aggarwal Shagun
Diagnostics Division, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India.
Diagnostics Division, Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India; Department of Medical Genetics, Nizam's Institute of Medical Sciences, Hyderabad, India.
Neuromuscul Disord. 2016 Nov;26(11):809-814. doi: 10.1016/j.nmd.2016.07.004. Epub 2016 Jul 16.
Schwartz-Jampel Syndrome type 1 is a rare autosomal recessive musculoskeletal disorder (OMIM #255800) caused by various mutations in the HSPG2 gene encoding protein perlecan, a ubiquitous heparan sulfate proteoglycan, which is an integral component of basement membranes and possesses angiogenic and growth-promoting attributes primarily by acting as a co-receptor for the basic fibroblast growth factors in human body. We report a novel homozygous intronic 5' splice site mutation in this gene (c.4740 + 5G>A) in a child with clinical features of Schwartz-Jampel syndrome type 1. The mutation was detected by exome sequencing and later confirmed by Sanger sequencing. The mother was found to be heterozygous for the mutation and an ongoing pregnancy found to be unaffected. cDNA analysis revealed skipping of exon 37 of HSPG2 gene in the patient due to the splicing error caused by this mutation. This is likely to result in loss of 38 amino acids from the domain III of the perlecan protein and presumably affects its structure and function as per protein modeling predictions. This report demonstrates the utility of exome sequencing as a routine molecular diagnostic approach of choice for this rare disorder.
1型施瓦茨 - 扬佩尔综合征是一种罕见的常染色体隐性肌肉骨骼疾病(OMIM编号:255800),由编码核心蛋白聚糖的HSPG2基因突变引起,核心蛋白聚糖是一种普遍存在的硫酸乙酰肝素蛋白聚糖,是基底膜的重要组成部分,主要通过作为人体碱性成纤维细胞生长因子的共受体而具有血管生成和促进生长的特性。我们报告了一名具有1型施瓦茨 - 扬佩尔综合征临床特征的儿童中该基因的一个新的纯合内含子5'剪接位点突变(c.4740 + 5G>A)。该突变通过外显子组测序检测到,随后通过桑格测序得到证实。发现母亲为该突变的杂合子,且正在进行的妊娠未受影响。cDNA分析显示,由于该突变导致的剪接错误,患者的HSPG2基因第37外显子跳跃。根据蛋白质模型预测,这可能导致核心蛋白聚糖蛋白结构域III中38个氨基酸缺失,并可能影响其结构和功能。本报告证明了外显子组测序作为这种罕见疾病常规分子诊断方法的实用性。