Ding Yibing, Zhu Chengchu, Zou Wei, Ma Dehua, Min Haiyan, Chen Baofu, Ye Minhua, Pan Yanqing, Cao Lei, Wan Yueming, Zhang Wenwen, Meng Lulu, Mei Yuna, Yang Chi, Chen Shilin, Gao Qian, Yi Long
Center for Translational Medicine, Nanjing University Medical School, Nanjing, China; Jiangsu Key Laboratory for Molecular Medicine, Nanjing University Medical School, Nanjing, China.
Am J Med Genet A. 2015 May;167A(5):1125-33. doi: 10.1002/ajmg.a.36979. Epub 2015 Mar 21.
Primary spontaneous pneumothorax (PSP) is a significant clinical problem, affecting tens of thousands patients annually. Germline mutations in the FLCN gene have been implicated in etiology of familial PSP (FPSP). Most of the currently identified FLCN mutations are small indels or point mutations that detected by Sanger sequencing. The aim of this study was to determine large FLCN deletions in PSP families that having no FLCN sequence-mutations. Multiplex ligation-dependent probe amplification (MLPA) assays and breakpoint analyses were used to detect and characterize the deletions. Three heterozygous FLCN intragenic deletions were identified in nine unrelated Chinese families including the exons 1-3 deletion in two families, the exons 9-14 deletion in five families and the exon 14 deletion in two families. All deletion breakpoints are located in Alu repeats. A 5.5 Mb disease haplotype shared in the five families with exons 9-14 deletion may date the appearance of this deletion back to approximately 16 generations ago. Evidences for founder effects of the other two deletions were also observed. This report documents the first identification of founder mutations in FLCN, as well as expands mutation spectrum of the gene. Our findings strengthen the view that MLPA analysis for intragenic deletions/duplications, as an important genetic testing complementary to DNA sequencing, should be used for clinical molecular diagnosis in FPSP.
原发性自发性气胸（PSP）是一个重大的临床问题，每年影响数以万计的患者。卵泡抑素基因（FLCN）的种系突变与家族性PSP（FPSP）的病因有关。目前鉴定出的大多数FLCN突变是通过桑格测序检测到的小插入缺失或点突变。本研究的目的是确定在没有FLCN序列突变的PSP家族中的大型FLCN缺失。采用多重连接依赖探针扩增（MLPA）分析和断点分析来检测和表征这些缺失。在9个不相关的中国家族中鉴定出3个杂合的FLCN基因内缺失，包括2个家族中的外显子1-3缺失、5个家族中的外显子9-14缺失和2个家族中的外显子14缺失。所有缺失断点均位于Alu重复序列中。在5个外显子9-14缺失的家族中共享的一个5.5 Mb疾病单倍型可能将这种缺失的出现追溯到大约16代以前。还观察到另外两个缺失存在奠基者效应的证据。本报告首次记录了FLCN中的奠基者突变，同时也扩展了该基因的突变谱。我们的研究结果强化了这样一种观点，即基因内缺失/重复的MLPA分析作为DNA测序的重要遗传检测补充手段，应用于FPSP的临床分子诊断。
