摘要
目的 本研究旨在鉴定1个居住于浙江省杭州市的疑似Bothnian型掌跖角化病(PPKB)家系的致病基因突变位点。方法 收集和分析患者的家系资料,采集患者及其双亲的外周血样本,抽提基因组DNA。先通过全外显子组测序(WES)方法分析和筛选潜在的突变基因及其位点,再用聚合酶链反应(PCR)和Sanger测序对候选基因突变进行验证。最后使用M-CAP、MutationTaster、FATHMM和PROVEAN软件分析预测突变蛋白可能的致病性。结果 本研究涉及的家系包含1例单发性女患者。研究结果显示,患者存在疑似水通道蛋白5基因(AQP5)第3外显子的杂合性错义突变:c.533A>C,导致其水通道蛋白5分子第178位的氨基酸由酪氨酸改变为丝氨酸(p.Tyr178Ser)。而患者的双亲均未发现该位点突变。提示该突变可能为新生突变(de novo mutation)。该突变在正常健康个体中的分布频率极低,尚未见报道。预测软件分析提示,依据美国医学遗传学与基因组学学会(ACMG)的标准与指南,该变异为疑似致病突变(PS2+PM2+PP3+PP4)。结合患者的临床特征,确诊为PPKB。结论 AQP5基因的杂合性错义突变c.533A>C(p.Tyr178Ser)可导致PPKB。用WES技术鉴定未确诊的疑难单基因病致病突变,高效而实用,检测结果有助于患者及其家系成员的遗传咨询、产前DNA诊断和疾病防治。
Objective To identify the mutation site of the pathogenic gene for a suspected Bothnian palmoplantar keratoderma(PPKB)family living in Hangzhou,Zhejiang province,China.Methods Data of the pedigree was collected and analyzed.Peripheral blood samples of the patient and her parents were drawn,and genomic DNA was extracted.First,whole exome sequencing(WES)was used to screen the potential disease-causing genes and their sites.Then polymerase chain reaction(PCR)and Sanger sequencing were applied to verify the candidate gene mutation.Finally,M-CAP,MutationTaster,FATHMM and PROVEAN software were used to analyze and predict the possible pathogenicity of the mutant protein.Results The family involved in our study included an isolated affected female patient.Research results showed that there was a heterozygous missense mutation within exon 3 of aquaporin 5 gene(AQP5),c.533A>C,which resulted in the amino acid change of 178 position of aquaporin 5 molecule from tyrosine to serine(p.Tyr178Ser).No mutation was found in the patient's parents,suggesting that the mutation a de novo accident.The distribution frequency of c.533a>C mutation among normal healthy individuals has not been reported yet.The analysis results of prediction software indicates that the mutation is a pathogenic mutation(PS2+PM2+PP3+PP4)according to the standards and guidelines of the American College of Medical Genetics and Genomics(ACMG).Combined with the clinical characteristics of the patient,PPKB was diagnosed.Conclusion The heterozygous missense mutation c.533a>C(p.Tyr178Ser)of AQP5 could lead to PPKB.WES is an efficient and practical approach to identify the pathogenic mutations of undiagnosed difficult monogenic disorders,and the detection is helpful for genetic counseling,prenatal DNA diagnosis and disease prevention and treatment of patients and their family members.
作者
彭立宇
王婧华
张宝燕
PENG Liyu;WANG Jinghua;ZHANG Baoyan(Department of Pathology,Hangzhou Hospital of Traditional Chinese Medicine,Hangzhou,Zhejiang 310007,China;Department of Pathology,the 903rd Hospital of the Joint Service Support Force of the Chinese People’s Liberation Army,Hangzhou,Zhejiang 310013,China)
出处
《中国优生与遗传杂志》
2023年第4期800-803,共4页
Chinese Journal of Birth Health & Heredity
