先天性特发性眼球震颤家系中GPR143基因的研究

目的验证我们所收集的家系在GPR143基因的已报道突变位点中是否有所相同。方法对本家系中的15个个体进行GPR143两个基因的外显子编码区进行基因突变检测,PCR扩增已以及纯化后进行GPR143基因的编码区测序。比对已报道的突变位点与本家系的关系以及直接测序分析寻找突变位点。结果通过验证发现我们的家系与目前所报道过的GPR143基因突变位点并无重复。结论通过验证发现我们的家系与目前所报道过的GPR143基因突变位点并无重复。排除了已报道过的突变位点,可以推测我们的家系中也许存在新的突变位点或是新的致病基因。     

先天性眼球震颤遗传学研究进展

先天性眼球震颤是一种不伴有其他明显眼病的眼科遗传病,该疾病的发生有很高的遗传异质性,已经发现多个致病基因基因座,Xq26–q27、Xp11.4-p11.3、13q31-q33和6p12,可能还有新的基因座没有被发现,已经研究的基因座致病基因侯选区域很大,在该区域的侯选基因太多,所以必须精细定位后,才有可能完成致病基因的克隆工作。本文对先天性眼球震颤遗传学的研究进展进行了综述。     

一个先天性静止性夜盲症家系致病基因的突变分析

目的 检测和分析河南1个常染色体显性先天性静止性夜盲症( autosomal dominant congenital stationary night blindness,ADCSNB)家系相关基因的致病突变.方法 从该家系14名成员的外周血提取基因组DNA,根据已报道的ADCSNB的3个致病基因的6个相关位点设计引物.利用PCR扩增相关位点所在的外显子,纯化扩增产物后进行正反向测序.结果 在该家系患者的RHO基因中发现了1个c.281C＞T的杂合错义点突变,该突变在蛋白质水平将导致p.Thr94Ile的改变,而在该家系正常成员以及50名正常对照中未发现此突变.结论 RHO基因c.281C＞T突变(p.Thr94Ile)为该家系先天性静止性夜盲症发病的分子遗传学基础.     

先天性小眼球致病基因的研究进展

先天性小眼球是一种先天发育异常性眼科疾病,遗传方式有常染色体显性遗传,常染色体隐性遗传和X连锁隐性遗传。迄今为止,用连锁分析和细胞遗传学方法对小眼球相关基因进行了基因定位并进一步对候选基因进行突变分析。本文就近年来先天性小眼球致病基因研究方面作一综述。     

一个先天性白内障家系缝隙连接蛋白基因新突变

目的 鉴定一个中国常染色体显性遗传先天性白内障(autosomal dominant congenital cataract,ADCC)家系其致病与缝隙连接蛋白a3/a8(gap junction protein alpha3/alpha8,GJA3/GJA8)基因突变的关系.方法 对一个ADCC家系5名家系成员和100名正常健康人进行全面眼科检查.抽取外周血5 mL并提取基因组DNA.采用聚合酶链反应扩增GJA3/CJA8编码外显子及其侧翼内含子序列,纯化的PCR产物通过直接测序以筛查致病突变.结果 通过双向序列分析,发现GJA8基因第2外显子的第138位发生碱基G→A转换(c.138G》A,GGG→GGA),产生同义突变(G46G);第139个碱基因G→T颠换发生错义突变(c.139 G》T,GAT→TAT)导致第47位编码天门冬氨酸密码子突变为酪氨酸(D47Y),家系中非患者和100名对照者基因组序列均无此改变,而且生物信息检索显示GJAB基因第47位编码的天门冬氨酸具有高度的物种保守性.家系3例患者CJA3基因突变筛查未见任何碱基改变.结论 在一个中国人ADCC家系中发现GJAB基因新致病突变(D47Y).     

先天性特发眼球震颤一家系

先证者(Ⅴ10)男,18岁。生后2个月发现患儿眼球左右摆动。右眼视力为0.08,左眼视力为0.10,双眼矫正视力均为-10.0D→0.2。双眼呈水平性眼球震颤,无中间带,无快慢相,向各方向转动无变化。伴有弱视、近视和斜视(外斜约35°)。精神紧张时眼球震颤频率加快,遮盖一只眼检查视力时摆动频率增加更为显著;精神放松时,摆动频率明显降低。无代偿头位。前后房、虹膜色素分布正常。眼底:双眼视盘边界清楚,血量走行正常,黄斑部无明显色素,中心反射未见。视网膜正常,晶状体透明,眼角膜薄,无法手术治疗,诊断为先天性特发眼球震颤。家系调查:该家系6代共44人…     

一个先天性无虹膜家系PAX6基因的新突变

目的 通过分子遗传学分析,确定中国东北地区一个先天性无虹膜家系PAX6基因的突变位点.方法 采集一个家系3例先天性虹膜患者及5名健康成员和100名正常对照者的外周静脉血,应用聚合酶链反应,直接测序法,单链构象多态性技术以及T载体克隆测序等方法确定其突变位点.结果 患者为第5外显子从483位点开始9个碱基缺失的框内缺失突变:其密码子位置为41～43,即缺失门冬氨酸、异亮氨酸和苏氨酸3个氨基酸(c.483del9).结论 PAX6基因是先天性无虹膜的致病基因,发现了PAX6基因一个新的突变位点.     

中国东北汉族一个先天性白内障家系致病基因的鉴定

目的鉴定一个先天性白内障家系的致病基因。方法根据已知与先天性白内障有关的12个致病基因的染色体上的定位,分别选取3～4个的微卫星标记位点,对该家系进行连锁分析。通过测序鉴定致病基因。结果在1q21.1GJA8位点显示最大Lod值2.44。致病基因定位于1q21.1区的GJA8基因,构成缝隙连接的缝隙连接蛋白Connexin50。DNA序列分析鉴定显示其第2外显子的第191个碱基杂合突变T>G导致其蛋白产物第64位缬氨酸转变为甘氨酸。结论Connexin50的V64G新生突变是导致该家系的致病原因。     

先天性室间隔缺损中的一个GATA4基因新突变

目的 研究GATA4基因新突变导致先天性室间隔缺损(ventricular septal defect,VSD)的分子机制.方法 收集185例先天性VSD患者的临床资料和血标本,以200名健康者为对照.应用PCR扩增GATA4基因的全部外显子,采用双脱氧核苷链末端合成终止法对全部扩增片段进行测序以识别基因突变.克隆GATA4基因,通过定位诱变获得相应的突变体,应用脂质体将GATA4基因重组表达质粒及心房利钠肽基因启动子启动绿色荧光蛋白表达的报告载体转染HeLa细胞,应用逆转录-PCR研究GATA4基因突变对其编码的转录因子的活性的影响.结果 在1例VSD患者的GATA4基因发现1个新的杂合错义突变c.191G＞A,即第64位的密码子由GGA变为GAA,导致第64位的甘氨酸变为谷氨酸,即G64E突变.细胞表达分析显示GATA4突变G64E使转录因子的活性降低.结论 在先天性VSD患者发现GATA4新突变G64E,该突变可能通过抑制转录因子的活性而参与先天性VSD.     

一个先天性无虹膜合并白内障家系PAX6基因突变研究

目的 鉴定一个先天性无虹膜合并白内障家系的致病是否与PAX6基因突变有关.方法 提取该家系全部12名存活成员和96名正常人外周血白细胞DNA,PCR扩增PAX6基因的第4～13编码外显子及侧翼内含子剪切区域,通过直接测序比较家系患者与正常人序列差异以确定致病突变.结果 对PAX6基因序列分析结果显示,该家系3例患者中均存在一个无义突变,而在正常人和家系中非受累成员中则未发现.无义突变位于PAX6基因第10外显子1143位核苷酸c.1143C>T,突变导致精氨酸替换为终止密码(R261X).结论 PAX6基因突变R261X是中国人先天性无虹膜合并白内障的致病突变.     

Novel homozygous, heterozygous and hemizygous FRMD7 gene mutations segregated in the same consanguineous family with congenital X-linked nystagmus

Congenital nystagmus (NYS) is characterized by bilateral, spontaneous, and involuntary movements of the eyeballs that most commonly presents between 2 and 6 months of life. To date, 44 different FRMD7 gene mutations have been found to be etiological factors for the NYS1 locus at Xq26-q27. The aim of this study was to find the FRMD7 gene mutations in a large eleven-generation Indian pedigree with 71 members who are affected by NYS. Mutation analysis of the entire coding region and splice junctions of the FRMD7 gene revealed a novel missense mutation, c.A917G, predicts a substitution of Arg for Gln at codon 305 (Q305R) within exon 10 of FRMD7. The mutation was detected in hemizygous males, and in homozygous and heterozygous states in affected female members of the family. This mutation was not detected in unaffected members of the family or in 100 unrelated control subjects. This mutation was found to be at a highly conserved residue within the FERM-adjacent domain in affected members of the family. Structure prediction and energetic analysis of wild-type FRMD7 compared with mutant (Q305R) revealed that this change in amino acid led to a change in secondary structure predicted to be an energetically unstable protein. The present study represents the first confirmation of FRMD7 gene mutations in a multigenerational Indian family and expands the mutation spectrum for this locus.     

一个先天性无虹膜家系PAX6基因突变研究

目的 对一个先天性无虹膜家系进行致病基因研究.方法 采集患者外周静脉血,提取基因组DNA.采用微卫星标记物D11S904和D11S935对1个先天性无虹膜家系进行连锁分析;采用直接测序对PAX6基因全部14个外显子,以及外显子内含子拼接部进行序列分析.结果 在微卫星位点D11S904获得LOD值为3.01.该家系患者PAX6基因第9外显子检出R240X突变,而家系正常人以及100名正常对照无此基因突变.结论 R240X再发突变是导致先天性无虹膜的突变热点.     

Identification of a novel GPR143 mutation in a large Chinese family with congenital nystagmus as the most prominent and consistent manifestation

Congenital nystagmus is characterized by involuntary, rhythmical, repeated oscillations of one or both eyes. We studied a large Chinese family with nystagmus as a prominent and consistent manifestation phenotype in nine patients to map and identify a disease-causing gene for nystagmus. X-linked recessive inheritance was observed in the family, and foveal hypoplasia was detected in some of the nine patients. The disease gene was mapped to an approximately 10.6 Mb region flanked by DXS996 and DXS7593 on Xp22 with a significant peak multipoint LOD score. Analysis of 21 candidate genes in the region revealed a novel p.S89F mutation in the second transmembrane domain of GPR143, a G protein-coupled receptor which causes ocular albinism when mutated. All male patients in the family were hemizygous for the mutation; the female carriers were heterozygous for the mutation. The p.S89F mutation was not identified in 100 normal females or 100 normal males. Our results indicate that a mutation in the GPR143 gene can cause a variant form of ocular albinism, with congenital nystagmus as the most prominent and only consistent finding in all patients in this Chinese family. These results expand the spectrum of clinical phenotypes associated with GPR143 mutations. J.Y. Liu and X. Ren contributed equally to this work.     

Novel mutations in FRMD7 in X-linked congenital nystagmus. Mutation in brief #963. Online

Congenital nystagmus is an eye movement disorder in which one or both eyes are in constant movement. It can be associated with a number of ocular or neurological diseases, or it can be inherited in an autosomal or X-linked fashion. The latter form is called idiopathic or motor nystagmus (CIN). Loci on the X chromosome (NYS1) and on 6p12 (NYS2), 7p11.2 (NYS3), and 13q31-q33 (NYS4) have been identified for CIN. The molecular characterization of NYS1 has recently been solved by Tarpey et al., who identified mutations in FRMD7, a gene of unclear function. We report five novel mutations in FRMD7 and confirm the role of this gene in the pathogenesis of X-linked congenital nystagmus.     

A novel MIP gene mutation associated with autosomal dominant congenital cataracts in a Chinese family

Background

The major intrinsic protein gene (MIP), also known as MIP26 or AQP0, is a member of the water-transporting aquaporin family, which plays a critical role in the maintenance of lifelong lens transparency. To date, several mutations in MIP (OMIM 154050) have been linked to hereditary cataracts in humans. However, more pathogenic mutations remain to be identified. In this study, we describe a four-generation Chinese family with a nonsense mutation in MIP associated with an autosomal dominant congenital cataract (ADCC), thus expanding the mutational spectrum of this gene.

Methods

A large four-generation Chinese family affected with typical Y-suture cataracts combined with punctuate cortical opacities and 100 ethnically matched controls were recruited. Genomic DNA was extracted from peripheral blood leukocytes to analyze congenital cataract-related candidate genes. Effects of the sequence change on the structure and function of proteins were predicted by bioinformatics analysis.

Results

Direct sequencing of MIP in all affected members revealed a heterozygous nucleotide exchange c.337C>T predicting an arginine to a stop codon exchange (p.R113X). The substitution co-segregated well in all the affected individuals in the family and was not found in unaffected members or in the 100 unrelated healthy controls. Bioinformatics analysis predicted that the mutation affects the secondary structure and function of the MIP protein.

Conclusions

We identified a novel mutation of MIP (p.R113X) in a Chinese cataract family. This is the first nonsense mutation of MIP identified thus far. This novel mutation is also the first disease-causing mutation located in the loop C domain of MIP. The results add to the list of mutations of the MIP linked to cataracts.     

原发性先天性淋巴水肿一家系VEGFR3基因突变分析

目的 对1个患原发性先天性淋巴水肿(prjmary congenital lymphoedema,PCL)汉族大家系进行遗传学研究,了解先天性淋巴水肿患病的分子遗传学基础.方法 对该家系12名成员(10名直系亲属、2名配偶)采样并提取DNA,选择已知的3个PCL相关致病基因位点,用荧光微卫星标记进行基因连锁定位.确定VEGFR3为致病基因后,对家系中的患者进行VEGFR3基因的突变检测,并与100名正常人进行对照分析.结果 该家系疾病与5q35.3区的微卫星标记D5S408连锁.对该区域的VEGFR3进行DNA测序,发现患者含有1个c.C3341T转换,该突变导致VEGFR3蛋白发生p.Pro1114Leu;该家系中所检测患者均发现携带该杂合突变.100名正常对照该位点的测序分析未能检测到该突变.结论 VEGFR3基因是最重要的PCL致病基因,该家系成员VEGFR-3的p.Pro1114Leu突变是患者患淋巴水肿的遗传基础.     

A novel missense mutation of the EDA gene in a Mongolian family with congenital hypodontia

X-linked hypohidrotic ectodermal dysplasia (HED) is a rare disease characterized by the hypoplasia or absence of eccrine glands, dry skin, scant hair, and dental abnormalities. Here, we report a Mongolian family with congenital absence of teeth inherited in an X-linked fashion. The affected members of the family did not show other HED characteristics, except hypodontia. We successfully mapped the affected locus to chromosome Xq12-q13.1, and then found a novel missense mutation, c.193C>G, in the ectodysplasin A (EDA) gene in all affected males and carrier females. The mutation causes arginine to be replaced by glycine in codon 65 (R65G) in the juxtamembrane region of EDA. In addition, 33% (3/9) of female carriers have a skewed X-chromosome inactivation pattern. Our result strongly suggests that the c.193C>G mutation is the disease-causing mutation in this family.Ran Tao, Buhe Jin, Shen Zheng Guo, and Wei Qing contributed equally to this work.