结节性硬化症的两个TSC2基因新发框移突变

Two novel TSC2 frameshift mutations in tuberous sclerosis complex

摘要:

该研究采用高通量测序对两个结节性硬化症 （TSC）家系先证者外周血DNA行TSC相关基因 （TSC1、TSC2）及其拼接序列检测，确定基因突变位点，针对突变位点设计扩增引物，采用聚合酶链反应和Sanger测序法对先证者及其父母外周血DNA行一代测序验证。两家系先证者分别存在TSC2基因c.3981-3982 insA （p.Asp1327AspfsX87）、c.4013-4014 delCA （p.Ser1338Cysfs）杂合突变。家系1先证者父母该位点均未见异常；家系2先证者母亲检出TSC2基因c.4013-4014 delCA杂合突变，先证者父亲、先证者外祖父母该位点未见异常。c.3981-3982 insA突变会导致氨基酸序列在第1413位提前终止编码，c.4013-4014 delCA突变导致氨基酸序列在第1412位提前终止编码，二者分别为家系1、家系2的致病突变，且均为新发框移突变，但与疾病的关系仍需要突变蛋白功能细胞模型和动物模型的进一步验证。

Abstract:

High-throughput sequencing was performed for the peripheral blood DNA from two probands in the family with tuberous sclerosis complex (TSC) to determine the sequences of TSC-related genes TSC1 and TSC2 and their splicing regions and identify mutation sites. Amplification primers were designed for the mutation sites and polymerase chain reaction and Sanger sequencing were used to verify the sequences of peripheral blood DNA from the probands and their parents. The two probands had c.3981-3982 insA (p.Asp1327AspfsX87) and c.4013-4014 delCA (p.Ser1338Cysfs) heterozygous mutations, respectively, in the TSC2 gene. The parents of proband 1 had no abnormalities at these two loci; the mother of proband 2 had c.4013-4014 delCA heterozygous mutation in the TSC2 gene, while the father and the grandparents of proband 2 had no abnormalities. c.3981-3982 insA mutation may cause early coding termination of amino acid sequence at the 1413th site, and c.4013-4014 delCA mutation may cause early coding termination of amino acid sequence at the 1412th site. These two mutations are the pathogenic mutations for families 1 and 2, respectively, and both of them are novel frameshift mutations, but their association with the disease needs to be further verified by mutant protein function cell model and animal model.