一个Alazami综合征家系的遗传学诊断与分析

目的对一个Alazami综合征家系进行遗传学病因分析。方法采集先证者及家系成员的外周血样, 提取基因组DNA, 行全外显子组测序, 生物信息学分析确定致病基因, Sanger测序对家系成员进行验证。结果该家系中两例患者均存在LARP7基因的母源性的c.94A>T(p.Lys32*)无义变异和父源性的c.1141A>G(p.Lys381Glu)的错义变异。根据美国医学遗传学与基因组学学会致病性标准分类和功能预测软件分析, 确定二者是该Alazami综合征家系的遗传学病因。结论本研究发现了LARP7基因两个未见报道的变异, 丰富了LARP7基因变异谱。     

一个肥厚型心肌病家系患者的表型和MYH7基因变异分析CSCD

目的对1个肥厚型心肌病家系(hypertrophic cardiomyopathy,HCM)进行表型和MYH7基因变异分析,明确其可能的致病原因,为其临床诊断提供依据。方法对1个HCM家系先证者进行96个遗传性心肌病相关基因全外显子靶向高通量测序,应用Sanger测序在家系成员和300名正常对照者中对可疑变异进行验证,在家系中进行基因型与临床表型的共分离分析。应用Clustal X软件进行变异基因在物种间的序列保守性分析,并采用相关生物信息学软件对变异进行致病性分析和功能预测。结果在先证者及12名家系成员中,6人的MYH7基因存在c.4124A>G(p.Tyr1375Cys)杂合变异,其中5人确诊为HCM患者,1人未达到HCM诊断标准,但出现心电图异常。在300正常对照中未检出该变异。序列保守性分析显示MYH7基因的p.Tyr1375Cys变异位于高度保守区域,生物信息学分析预测该变异可能影响蛋白功能,为有害变异。根据美国医学遗传学与基因组学学会遗传变异分类标准与指南,MYH7基因c.4124A>G(p.Tyr1375Cys)变异判定为可能致病(PM2+PP1_Moderate+PP3+PP5)。结论MYH7基因c.4124A>G(p.Tyr1375Cys)变异可能是该家系的主要致病基因,基因检测结果对HCM家系患者早期诊断具有重要的意义。     

一个L1CAM基因新变异导致的HSAS综合征的家系分析

目的对1个HSAS综合征家系L1CAM基因进行变异分析,明确该家系脑积水胎儿的致病原因,为家系的遗传咨询和产前诊断提供依据。方法收集孕中期经超声发现胎儿脑积水引产儿的DNA,进行全外显子测序,并用Sanger测序对疑似致病变异进行家系验证。结果胎儿L1CAM基因(OMIM*308840)存在c.620A>G(p.Tyr207Cys)半合子变异,胎儿姐姐与母亲携带c.620A>G(p.Tyr207Cys)杂合变异,其父亲、外祖父母、舅舅该位点均为野生型。依据美国医学遗传学与基因组学学会变异分类标准与指南,该变异为可能致病变异(PM1+PM2+PP3+PP4)。结论L1CAM基因的c.620A>G半合子变异很可能是该家系胎儿的致病原因。     

一例Donohue综合征新生儿的基因变异分析

目的从分子水平明确1例疑似为Donohue综合征的新生儿的诊断。方法对患儿进行全外显子组测序(whole exome sequencing,WES),之后用Sanger测序和实时定量PCR对候选变异进行验证。结果WES检出患儿携带INSR基因的两处杂合变异,即c・3258+4(IVS17)A>G和第2外显子缺失,其中前者为新发现的变异。家系分析显示上述变异分别遗传自患儿的母亲和父亲,并经Sanger测序和实时定量PCR证实。结论INSR基因c.3258+4(IVS17)A>G和第2外显子杂合缺失所构成的复合杂合变异可能是导致患儿发病的原因。     

全外显子组测序技术检测一家系非综合征型唇腭裂基因突变

目的通过全外显子组测序技术,检测非综合征型唇腭裂家系致病基因新型突变。为该家系产前诊断以及遗传咨询提供可靠的遗传学依据。方法经知情同意,对死胎接生术后的胎儿进行检测。分析整理孕妇家系资料并绘制系谱图,采用高通量测序技术(NGS)对引产胎儿进行全外显子组测序,找到死产胎儿的高度可疑致病突变位点,并用Sanger测序的方法对家系成员一一验证。结果该家系中共5人,1名患者为非综合征型轻微唇裂,已实施手术修复。2名已故患者,由家系成员自述均为孕20w左右,B超提示严重唇腭裂,行死胎接生术,引产胎儿外观均符合唇腭裂表型。采用高通量测序技术(NGS)对引产胎儿行全外显子组测序,检测到先证者CDON c.323G>C(p.Ser108Thr)的错义突变;Sanger测序证实该家系中现存1人携带CDON c.323G>C(p.Ser108Thr)错义突变,为非综合征型轻微唇裂,已实施手术修复。该位点变异导致第108号氨基酸由Ser变为Thr(p.Ser108Thr),该变异可能导致蛋白功能受到影响,经家系验证该位点突变源自胎儿姥姥。生物信息学分析预测这种新型突变会引发蛋白功能异常。结论研究筛选出先证者及家系成员CDON基因的新型突变,该家系中携带CDON c.323G>C突变的成员临床表型差异较大,CDON基因符合常染色体显性遗传方式,结合常染色体显性遗传的外显率不同以及该家系的检测结果,认为CDON c.323G>C突变有可能是本家系致病的分子基础。     

口-面-指综合征一个家系的表型与遗传学分析

目的探讨1个口-面-指综合征Ⅰ型(OFD1)家系的临床表型及遗传学原因。方法选取2021年3月17日至河北省人民医院就诊的1个OFD1家系为研究对象。收集先证者临床资料对该家系的成员进行家系全外显子组测序(WES), 并通过Sanger测序进行验证。结果先证者表现为宽眼距、宽鼻根、鼻尖扁平, 分叶舌、舌赘生物, 左手小指呈弯曲状, 右手小指与无名指并指, 智力及语言发育落后。WES结果提示先证者及其女儿、妹妹和母亲均携带OFD1基因c.224A>G(p.Asn75Ser)杂合变异, 家系中的其他成员未携带同样的变异。结论 c.224A>G(p.Asn75Ser)杂合变异可能是导致该家系表型异常的原因, 上述发现丰富了OFD1基因的变异谱。     

以动眼神经麻痹为表现的2型神经纤维瘤病患者1例的临床特点及遗传学分析

目的报告1例以动眼神经麻痹为首发症状的2型神经纤维瘤病(NF2)患者, 并探讨其遗传学病因。方法选择2021年7月10日就诊于首都医科大学附属北京地坛医院的1例NF2患者作为研究对象。对患者及其父母进行全脑、全脊髓MRI检查, 追溯其家族史, 采集家系成员的外周血样, 提取DNA并进行全外显子组测序。对候选变异进行Sanger测序家系验证。结果影像学检查显示患者存在双侧前庭神经鞘瘤、海绵窦区脑膜瘤、腘窝神经源性肿瘤、皮下多发结节等。基因测序证实其NF2基因第8外显子存在c.757A>T新发无义变异, 导致第253位的赖氨酸替换为终止密码子, 导致编码的Merlin蛋白从第253位以后的氨基酸丢失。该变异未见健康人群公共数据库收录, 生物信息学软件预测其氨基酸序列高度保守。根据美国医学遗传学与基因组学学会(ACMG)相关指南判定为致病性变异(PVS1+PS2+PM2_Supporting+PP3+PP4)。结论该患者发病较早, 症状不典型且较重, 其遗传学病因为NF2基因c.757A>T(p.K253*)杂合无义变异。上述发现丰富了NF2基因的变异谱。     

IRF6基因变异所致van der Woude综合征一个家系的遗传学分析

目的探讨1个van der Woude综合征(VWS)家系的遗传学特征, 并为其提供生育指导。方法选取2020年5月因"2次唇腭裂儿妊娠史"在南京鼓楼医院就诊的1例先证者及其家系成员为研究对象。应用家系全外显子组测序(trio-WES)对先证者及其父母进行致病变异筛选, 针对候选致病变异进行Sanger测序家系验证(4代共8人)和生物信息学分析。对该家系中的胎儿进行染色体微阵列分析(CMA)以排除拷贝数变异。结果 Trio-WES发现先证者及其父亲携带IRF6: c.742G>T(p.G248C)杂合变异, 其母亲该位点为野生型。该变异为错义变异, 位于重要的蛋白质功能结构区, 在正常参考人群基因数据库中未见报道, 多种软件预测该变异影响蛋白质结构/功能的可能性较大, 与该家系中患者特异性表型高度相关, 且Sanger测序结果显示家系中8名成员(包括3名患者)的基因型与表型共分离。依据美国医学遗传学与基因组学学会(ACMG)相关指南, 评估为可能致病性变异(PM1+PM2_Supporting+PP1+PP3+PP4)。据此结果对先证者进行植入前遗传学诊断, ...     

一个肥厚型心肌病家系患者的表型和 MYH7基因变异分析

目的对1个肥厚型心肌病家系(hypertrophic cardiomyopathy, HCM)进行表型和MYH7基因变异分析, 明确其可能的致病原因, 为其临床诊断提供依据。方法对1个HCM家系先证者进行96个遗传性心肌病相关基因全外显子靶向高通量测序, 应用Sanger测序在家系成员和300名正常对照者中对可疑变异进行验证, 在家系中进行基因型与临床表型的共分离分析。应用Clustal X软件进行变异基因在物种间的序列保守性分析, 并采用相关生物信息学软件对变异进行致病性分析和功能预测。结果在先证者及12名家系成员中, 6人的MYH7基因存在c.4124A>G(p.Tyr1375Cys)杂合变异, 其中5人确诊为HCM患者, 1人未达到HCM诊断标准, 但出现心电图异常。在300正常对照中未检出该变异。序列保守性分析显示MYH7基因的p.Tyr1375Cys变异位于高度保守区域, 生物信息学分析预测该变异可能影响蛋白功能, 为有害变异。根据美国医学遗传学与基因组学学会遗传变异分类标准与指南, MYH7基因c.4124A>G(p.Tyr1375Cys)变异判定为可能致病(P...     

一个复合杂合变异致遗传性凝血因子Ⅺ缺陷症家系分析

目的探讨一个遗传性凝血因子XI(coagulation factor Ⅺ, FⅪ)缺陷症家系成员的分子致病机制。方法提取外周血基因组DNA, 并采用Sanger测序法检测先证者的15个外显子、侧翼序列及家系成员的相应变异外显子区域, 并用反向测序予以验证;ClustalX-2.1-win软件分析变异氨基酸位点的保守性;用Mutation Taster、PolyPhen2、PROVEAN三个在线生物信息学软件分析变异的致病性;用Swiss-pdbViewer软件分析变异氨基酸对蛋白质结构的影响。结果基因分析显示先证者第10外显子存在c.1107C>A(p.Tyr369stop)杂合无义变异以及第13外显子存在c.1562A>G(p.Tyr521Cys)杂合错义变异;其父亲携带c.1107C>A杂合无义变异, 其母亲和女儿均携带c.1562A>G杂合错义变异, 丈夫为野生型。保守性分析表明Tyr521在进化过程中为高度保守位点。变异碱基致病性预测发现c.1107C>A和c.1562A>G均为致病性变异。蛋白质模型分析显示在野生型FⅪ蛋白结构中, Tyr5...     

Epidemiology of Van der Woude syndrome from mutational analyses in affected patients from Pakistan

Malik S, Kakar N, Hasnain S, Ahmad J, Wilcox ER, Naz S. Epidemiology of Van der Woude syndrome from mutational analyses in affected patients from Pakistan. Mutations in IRF6 cause Van der Woude syndrome (VWS), one of the most common syndromes associated with cleft lip (CL) with or without cleft palate (CP). The presence of pits on the lower lip of patients is the most characteristic feature of the syndrome. We have identified three novel and seven previously reported IRF6 mutations in 12 of 16 unrelated families segregating VWS from Pakistan. The three newly identified mutations include a frameshift (c.568delG) and two missense mutations c.295G>A (p.G99S) and c.1219T>C (p.S407P). Recent functional studies on IRF6 and the three‐dimensional structure of IRF5 carboxy (C) terminus, a protein encoded by a paralog of IRF6, shed light on the p.S407P substitution. Additionally, the identification of the same mutations responsible for VWS in Pakistan, as reported in other global populations worldwide, marks these residues as mutational hotspots and indicates their essential role in structural stability or function of IRF6. This is the first study of VWS in Pakistan and we estimate that 1 in 100 patients with CL with or without CP (CL/P) are affected in the Pakistani population predominantly from the Punjab area.     

一个丙酸血症家系的PCCB基因两个新变异鉴定

目的分析1个丙酸血症(propionic acidemia,PA)家系的致病变异。方法通过多重探针杂交富集患儿PCCA和PCCB基因的全部编码外显子及其侧翼区序列进行高通量测序,检测可疑变异,运用Sanger测序在家系中进行变异验证。提取患儿父亲外周血淋巴细胞RNA,应用逆转录-聚合酶链反应联合Sanger测序对新剪切变异进行验证;采用多种在线软件对错义变异进行致病性分析。结果在患儿PCCB基因第1内含子和第7外显子检出复合杂合变异,分别是c.184-2A>G剪切变异和c.733G>A(p.G245S)错义变异,Sanger测序验证表明二者分别来自父母。mRNA水平验证表明,c.184-2A>G变异可导致PCCB基因转录产物第2外显子的缺失;多个软件预测c.733G>A错义变异具有致病性,245位置的氨基酸在不同物种均具有高度保守性。结论PCCB基因变异可能是该家系患儿的致病原因,新变异的检出丰富了PCCB基因的变异谱。     

一个常染色体显性遗传腓骨肌萎缩病2A2A型家系的基因变异分析

目的:对1个腓骨肌萎缩病家系进行基因变异分析,明确其遗传学病因。方法:对先证者进行神经电生理检查和全外显子组基因测序,用Sanger测序技术对先证者及其家系进行变异位点验证。应用计算机软件预测变异位点氨基酸进化保守性和变异可能导致的蛋白质结构和功能变化,分析变异位点的性质。结果:先证者神经电生理检查示运动和感觉神经纤维...     

Maternal MTHFR variant forms increase the risk in offspring of isolated nonsyndromic cleft lip with or without cleft palate

The pathogenesis of cleft lip with or without cleft palate (CL/P) is complex; its onset could be due to the interaction of various genetic and environmental factors. Recently MTHFR functional polymorphisms were found to increase the risk of this common malformation; however, this finding is still debated. We investigated 110 sporadic CL/P patients, their parents and 289 unrelated controls for c.665C>T (commonly known as 677C>T; p.Ala222Val) and c.1286A>C (known as 1298A>C; p.Glu429Ala) polymorphism in the MTHFR gene. Transmission disequilibrium test (TDT) showed no distortion in allele transmission. Nevertheless, association studies revealed significant differences in allele frequencies between mothers of CL/P patients and controls. This work supports the hypothesis that a lower MTHFR enzyme activity in pregnant women, mostly related to the c.665C>T variant form, is responsible for a higher risk of having CL/P affected offspring.     

西北地区人群JAG2基因多态性与非综合征性唇腭裂的相关性研究

目的探讨JAG2基因多态性与西北地区人群非综合征性唇腭裂(nonsyndromic cleft lip with or without cleft palate,NSCLP)的相关性。方法采用病例-对照研究方法,选取NSCLP患者301例,正常对照304人,采用iMLDR™基因分型技术对JAG2基因的3个单核苷酸多态性(single nucleotide polymorphism,SNP)位点[rs741859(T/C)、rs11621316(A/G)以及rs1057744(C/T)]进行分型,比较其等位基因、基因型及所构建的单倍型在两组人群中的分布差异。结果rs741859位点等位基因C和T在NSCLP组和对照组中的分布差异有统计学意义。rs741859位点CT基因型可将NSCLP的患病风险显著降低至65%(P<0.05),将唇裂伴或不伴腭裂(cleft lip with or without cleft palate,CL/P)的患病风险降低至62%(P<0.05);而rs11621316、rs1057744处于同一连锁不平衡(linkage disequilibrium,LD)区域,连锁程度较高(r2>0.8),其基因型、等位基因在两组中的分布差异无统计学意义(P>0.05)。结论JAG2基因rs741859位点CT基因型可能是中国西北人群NSCLP的保护性基因型。     

Resolving clinical diagnoses for syndromic cleft lip and/or palate phenotypes using whole‐exome sequencing

Individuals from three families ascertained in Bogota, Colombia, showing syndromic phenotypes, including cleft lip and/or palate, were exome‐sequenced. In each case, sequencing revealed the underlying causal variation confirming or establishing diagnoses. The findings include very rare and novel variants providing insights into genotype and phenotype relationships. These include the molecular diagnosis of an individual with Nager syndrome and a family exhibiting an atypical incontinentia pigmenti phenotype with a missense mutation in IKBKG. IKBKG mutations are typically associated with preterm male death, but this variant is associated with survival for 8–15 days. The third family exhibits unusual phenotypic features and the proband received a provisional diagnosis of Pierre Robin sequence (PRS). Affected individuals share a novel deleterious mutation in IRF6. Mutations in IRF6 cause Van der Woude and popliteal pterygium syndrome and contribute to nonsyndromic cleft lip phenotypes but have not previously been associated with a PRS phenotype. Exome sequencing followed by in silico screening to identify candidate causal variant(s), and functional assay in some cases offers a powerful route to establishing molecular diagnoses. This approach is invaluable for conditions showing phenotypic and/or genetic heterogeneity including cleft lip and/or palate phenotypes where many underlying causal genes have not been identified.     

SPTB基因c.5798+1G>A新变异导致遗传性球形红细胞增多症一家系

目的对一个遗传性球形红细胞家系致病基因进行鉴定和突变致病性分析。方法采集该家系共17人的外周血样。采用高通量测序分析先证者外周血DNA,筛选候选致病变异并进行家系共分离分析。然后采用同源重组构建pCAS2c.5798+1G和pCAS2c.5798+1A型质粒,转染293T细胞,应用反转录PCR、TA克隆和Sanger测序分析候选致病变异对剪接的影响,同时提取患者外周血RNA,分析候选致病变异在体内的剪接情况。结果高通量测序结果显示先证者携带SPTB基因c.5798+1G>A变异,且该变异与家系患者的表型共分离。体、内外剪接实验结果显示c.5798+1G>A变异明显影响RNA的正常剪接,导致阅读框移码产生提前终止的密码子。结论SPTB基因c.5798+1G>A新变异是导致该家系遗传性球形红细胞症的原因。     

Variation in IRF6 contributes to nonsyndromic cleft lip and palate

Nonsyndromic cleft lip with or without cleft palate (NSCLP) is a common craniofacial birth defect which results in lifelong medical and social consequences. While there have been a number of attempts to identify the genes responsible for this disorder, the results have not been consistent among populations and no single gene has been identified as playing a major susceptibility role. Van der Woude syndrome, a disorder characterized by lower-lip pits with or without cleft lip/palate, results in many cases from mutations in the interferon regulatory factor 6 (IRF6) gene. Recently, Zucchero et al. [2004: N Engl J Med 351:769-780] detected an association between SNPs in IRF6 and NSCLP in a number of different populations. A subsequent study by Scapoli et al. [2005: Am J Hum Genet 76:180-183] confirmed this association in an Italian population. We examined the same SNPs as Scapoli et al. [2005] in our large, well-characterized sample of NSCLP families and trios, and also detected an altered transmission of IRF6 alleles. This additional confirmation further strengthens the IRF6 association and suggests that IRF6 plays a role in NSCLP susceptibility.