一个中国原发性开角型青光眼家系致病基因研究

目的:鉴定一个江苏省南通市原发性开角型青光眼(POAG)家系的青光眼致病基因,分析该基因的临床表型和致病机制。方法:于2020-01/12回顾并招募了一个POAG家系,该家系跨越5代共33名,有13名家庭成员参与了研究,其中4名诊断为POAG,1名诊断为高眼压症,剩余8名未受影响。详细询问病史并进行全面的眼科检查,采用高通量测序筛选可能的致病基因,Sanger测序验证候选致病基因。结果:该家系患者均在青年时期发现眼压升高并诊断为青光眼,需手术治疗控制眼压,先证者最高眼压(IOP)达55mmHg。全外显子测序在先证者LTBP2基因上发现了一个杂合突变(c.1197C>A, p.Phe399Leu),Sanger测序验证该突变位点与家系疾病并不分离。结论:LTBP2 (c.1197C>A)突变不是该家系POAG的致病基因。但是LTBP2突变在POAG病例中的致病作用值得研究。     

A novel CRX mutation by whole-exome sequencing in an autosomal dominant cone-rod dystrophy pedigree

AIM: To identify the disease-causing gene mutation in a Chinese pedigree with autosomal dominant cone-rod dystrophy (adCORD). METHODS: A southern Chinese adCORD pedigree including 9 affected individuals was studied. Whole-exome sequencing (WES), coupling the Agilent whole-exome capture system to the Illumina HiSeq 2000 DNA sequencing platform was used to search the specific gene mutation in 3 affected family members and 1 unaffected member. After a suggested variant was found through the data analysis, the putative mutation was validated by Sanger DNA sequencing of samples from all available family members. RESULTS: The results of both WES and Sanger sequencing revealed a novel nonsense mutation c.C766T (p.Q256X) within exon 5 of CRX gene which was pathogenic for adCORD in this family. The mutation could affect photoreceptor-specific gene expression with a dominant-negative effect and resulted in loss of the OTX tail, thus the mutant protein occupies the CRX-binding site in target promoters without establishing an interaction and, consequently, may block transactivation. CONCLUSION: All modes of Mendelian inheritance in CORD have been observed, and genetic heterogeneity is a hallmark of CORD. Therefore, conventional genetic diagnosis of CORD would be time-consuming and labor-intensive. Our study indicated the robustness and cost-effectiveness of WES in the genetic diagnosis of CORD.     

全外显子组测序检测到一视网膜色素变性家系ABCA4基因致病剪切新突变

目的探讨一个中国视网膜色素变性（RP）家系的致病基因及其位点。方法实验研究。对一个RP家系的成员进行病史采集、视力检查、眼底检查及多焦视网膜电图（mfERG）检查。绘制家系图,对家系成员采血,进行DNA提取、全外显子组测序、数据分析和Sanger测序验证,并在500例健康对照者中进行测序验证。结果共纳入该家系成员5例,含2例患者。患者表现为青少年期发病,夜盲,进行性周边视力受损,逐渐累及中央区。眼底检查显示视网膜色素沉着。mfERG显示a波、b波振幅明显下降甚至记录不到。家系特点为2例患者为姐妹,另一位姐妹正常,父母均正常,符合常染色体隐性遗传模式特征。经外显子组测序、数据分析和Sanger测序验证后,发现ABCA4变异性剪切位点c.1761-2A>G发生纯合突变。另外,在500例健康对照者中,Sanger测序没有发现该位点纯合突变。结论本研究发现了一个新的视网膜色素致病基因突变位点c.1761-2A>G,扩大了ABCA4致病基因位点谱,为临床的诊断和治疗提供了新靶点。     

一Stickler综合征家系的临床特征及分子遗传学分析

目的：:研究一Stickler综合征家系的临床表型及分子遗传学特点,并确定致病基因及其突变。方法：:实验研究。对一Stickler综合征家系4代11例患者进行临床特征及系谱分析。采集该家系先证者及其他成员（患者及正常人）的外周静脉血标本,并利用高通量二代测序技术对先证者及正常对照样本行全外显子组测序（WES）分析。针对...     

常染色体隐性遗传视网膜色素变性家系视紫红质基因突变的检测分析

目的 观察一个近亲婚配常染色体隐性遗传视网膜色素变性（ARRP）家系中视紫红质基因（RHO）的突变特征，并探讨其视网膜色素变性(RP)发病机制。 方法 抽取8例该ARRP家系成员及10例正常对照者的外周静脉血5~8 ml；提取基因组DNA；采用聚合酶链反应（PCR）方法扩增RHO基因第1~5外显子和第1内含子基因 片段 ，用直接DNA测序法筛查RHO基因突变。 结果 来自同一家系3例患者RHO 基因的第5外显子第344密码子发生了A→G碱基的错义突变，导致了谷氨酰胺变成了精氨酸(G ln344Arg)，3例患者为该突变的纯合子。患者近亲婚配父母及1例未患病家庭成员为该突变 的杂合子。2例未患病家庭成员及10例正常对照者均未发现RHO基因突变。 结论 Gln344Arg突变可能是该ARRP家系的致病原因；在近亲婚配ARRP家系中RHO基因突变频率可能增加。 （中华眼底病杂志，2004，20：145-148）     

Whole-exome sequencing identifies novel mutations in genes responsible for retinitis pigmentosa in 2 nonconsanguineous Chinese families

AIM: To detect the pathogenetic mutations responsible for nonsyndromic autosomal recessive retinitis pigmentosa (RP) in 2 nonconsanguineous Chinese families. METHODS: The clinical data, including detailed medical history, best corrected visual acuity (BCVA), slit-lamp biomicroscope examination, fundus photography, optical coherence tomography, static perimetry, and full field electroretinogram, were collected from the members of 2 nonconsanguineous Chinese families preliminarily diagnosed with RP. Genomic DNA was extracted from the probands and other available family members; whole-exome sequencing was conducted with the DNA samples provided by the probands, and all mutations detected by whole-exome sequencing were verified using Sanger sequencing in the probands and the other available family members. The verified novel mutations were further sequenced in 192 ethnicity matched healthy controls. RESULTS: The patients from the 2 families exhibited the typical symptoms of RP, including night blindness and progressive constriction of the visual field, and the fundus examinations showed attenuated retinal arterioles, peripheral bone spicule pigment deposits, and waxy optic discs. Whole-exome sequencing revealed a novel nonsense mutation in FAM161A (c.943A>T, p.Lys315*) and compound heterozygous mutations in RP1L1 (c.56C>A, p.Pro19His; c.5470C>T, p.Gln1824*). The nonsense c.5470C>T, p.Gln1824* mutation was novel. All mutations were verified by Sanger sequencing. The mutation p.Lys315* in FAM161A co-segregated with the phenotype, and all the nonsense mutations were absent from the ethnicity matched healthy controls and all available databases. CONCLUSION: We identify 2 novel mutations in genes responsible for autosomal recessive RP, and the mutation in FAM161A is reported for the first time in a Chinese population. Our result not only enriches the knowledge of the mutation frequency and spectrum in the genes responsible for nonsyndromic RP but also provides a new target for future gene therapy.     

Genetic analysis of Chinese families reveals a novel truncation allele of the retinitis pigmentosa GTPase regulator gene

AIM: To make comprehensive molecular diagnosis for retinitis pigmentosa (RP) patients in a consanguineous Han Chinese family using next generation sequencing based Capture-NGS screen technology. METHODS: A five-generation Han Chinese family diagnosed as non-syndromic X-linked recessive RP (XLRP) was recruited, including four affected males, four obligate female carriers and eleven unaffected family members. Capture-NGS was performed using a custom designed capture panel covers 163 known retinal disease genes including 47 RP genes, followed by the validation of detected mutation using Sanger sequencing in all recruited family members. RESULTS: Capture-NGS in one affected 47-year-old male reveals a novel mutation, c.2417_2418insG:p.E806fs, in exon ORF15 of RP GTPase regulator (RPGR) gene results in a frameshift change that results in a premature stop codon and a truncated protein product. The mutation was further validated in three of four affected males and two of four female carriers but not in the other unaffected family members. CONCLUSION: We have identified a novel mutation, c.2417_2418insG:p.E806fs, in a Han Chinese family with XLRP. Our findings expand the mutation spectrum of RPGR and the phenotypic spectrum of XLRP in Han Chinese families, and confirms Capture-NGS could be an effective and economic approach for the comprehensive molecular diagnosis of RP.     

全外显子组测序法对中国先天性白内障一家系致病基因的研究

背景 基因突变是导致遗传性先天性白内障的主要原因,全外显子组测序技术是目前研究致病基因突变较为理想的检测手段. 目的 应用高通量测序技术对中国汉族常染色体显性遗传先天性白内障(ADCC)一家系的3例患者进行全外显子组测序,筛选该ADCC家系的致病基因. 方法 采用横断面研究方法,收集中国汉族先天性白内障一家系,共有4代48人家系成员,其中Ⅰ1和Ⅰ2已去世.在Ⅱ、Ⅲ、Ⅳ代中各取1例患者的静脉血8 ～ 10 ml,采用全外显子捕获和新一代测序技术进行高通量测序,测序结果与人类HA PMAP8、dbSNP130和1000 Genome Project数据库进行比对,过滤已报道的常见变异后,再过滤掉同义突变,最后通过Sanger法测序排除外显子测序的假阳性结果,筛选出候选基因,并对其进行突变筛查.结果 该家系的所有成员中共11例患病者,且各代均有患病者,男女发病比例相当,符合ADCC的遗传规律,所有患者均为核性白内障.全外显子组测序发现,在各候选基因中,主要内源性蛋白(MIP)基因是ADCC的已知基因,故采用Sanger法首先对MIP基因进行验证并确定杂合突变(chr12:56845250 C＞T)为该家系的致病突变.该突变位于剪切位点上,造成由第4外显子编码的61个氨基酸被亮氨酸-组氨酸-丝氨酸所替代,导致异常截短蛋白的产生.结论 MIP基因剪切位点的杂合突变是导致该ADCC家系致病的分子发病机制.     

目标区域捕获测序检测到一视网膜色素变性家系ABCA4基因新突变

目的研究我国一个常染色体隐性遗传的视网膜色素变性（RP）家系患者的临床表型及致病基因突变,并分析表型与基因型间的关系。方法实验研究。收集了宁夏人民医院眼科诊治的一个RP家系的临床资料,共有7名家庭成员参与研究,其中包括2名患者和5名正常成员。完善家系内所有参与成员的眼科检查,包括最佳矫正视力（BCVA）、视野、眼底照相、光学相干断层扫描（OCT）及全视野视网膜电流图（ERG）等。针对180个已知的遗传性视网膜疾病致病基因及9个高度可疑的候选基因设计目标区域捕获芯片,利用该捕获芯片对先证者（Ⅳ-4）进行目标区域内的高通量二代测序,借助优化的生物信息学分析对捕获的遗传变异进行筛查过滤,最终通过家系内共分离验证确认致病突变,进一步分析该突变与患者表型间的关系。结果临床检查结果表明该家系内的2名患者的临床表现均符合典型的RP改变,遗传学分析结果证实了ABCA4基因c.419G>A突变是该家系的致病突变。该突变导致了ABCA4基因所编码的蛋白第140号氨基酸由精氨酸变为谷氨酰胺（p.Arg140Gln）,保守性分析显示该突变位点在各物种中高度保守,PloyPhen-2软件预测结果表明该突变具有较高的致病性。结论本研究借助基于高通量二代测序平台的目标区域捕获测序,首次发现了ABCA4基因新突变p.Arg140Gln是一个常染色体隐性遗传RP家系的致病突变,进一步扩充了ABCA4基因的遗传突变谱及表型谱。     

Rhodopsin C110Y mutation causes a type 2 autosomal dominant retinitis pigmentosa

Purpose: The RHO C110Y mutation has been recently reported to cause a phenotypically unspecified form of autosomal dominant retinitis pigmentosa (adRP). The study of a family affected with this mutation allowed us to hereby describe the genotype/phenotype correlation associated with the RHO C110Y mutation. Methods: A six-generation pedigree cosegregating adRP and RHO C110Y in ten accessible individuals was ophthalmologically investigated. All family members affected with RP went through complete eye examination and ERG testing. Results: The disease first manifested with nyctalopia during adulthood and slowly progressed over the next decades towards tubular visual field defects and relatively preserved central vision. Ophthalmoscopically, the fundus remained almost unaltered until the end of the third decade of life, and then slowly progressed towards typical RP changes with minimal macular involvement by the eighth decade. Color vision remained unaltered. Earliest ERG alteration was limited to the rod system followed by a rod-cone pattern. Scotopic and photopic ERG were recordable until the fourth and sixth decades, respectively. Discussion: RHO C110Y-associated adRP is characterized by a late onset and a mild progression compatible with type 2 or regional RP with little intrafamilial phenotypic variability and complete penetrance. Characterization of genotype-phenotype correlations plays a role in the improvement of genetic and prognostic counselling.     

Novel RPGR mutations with distinct retinitis pigmentosa phenotypes in French-Canadian families

PURPOSE: To characterize the molecular defects in two x-linked retinitis pigmentosa (RP) families. We hypothesized that different RPGR mutations result in distinct RP phenotypes. DESIGN: Observational case series. METHODS: Fifteen members in family I and three members in family II were evaluated. Full ophthalmic evaluations were done. Linkage analyses were performed and likelihood of odds scores (LOD score) were calculated. For mutation analyses, we used dHPLC and automated sequencing. RESULTS: Two novel RPGR mutations were identified in the two families; a Glu 414 (2-bp del) frameshift mutation in family I and an IVS 2-1 (g to a) splice site mutation in family II. All male family members in family I were severely affected by RP but maintained central visual acuities until their 50s and did not develop a bull's eye maculopathy. The female phenotype was highly variable. Some of the carriers exhibited a severe phenotype, one female displayed an asymmetric phenotype, and other carriers were asymptomatic. All members with the RPGR frameshift mutation exhibited rod-cone electroretinograms abnormalities, whereas five members had hearing loss. Male members of family II were severely affected, with early visual acuity loss, central scotomas, and bull's eye maculopathy. The female family members were asymptomatic but displayed cone-rod electroretinograms changes. There was no hearing loss. CONCLUSIONS: Different RPGR mutations lead to distinct RP phenotypes, with a highly variable inter- and intrafamilial phenotypic spectrum of disease that is associated with the type of mutation in RPGR and nonrandom X chromosome inactivation, respectively.     

Usher综合征一家系的致病基因分析

目的：对一Usher综合征家系的临床特征进行分析,探索该家系的致病基因。

方法：收集于我院就诊的一视网膜色素变性家系,详细询问患者病史并进行临床检查,诊断为Usher综合征,抽取家系成员静脉血4mL,提取全基因组DNA,对先证者进行靶向捕获高通量测序获得突变位点,对于筛选出的可疑突变扩展至家系全体成员进行Sanger测序验证,同时在100名正常对照者中验证。

结果：患者除视网膜色素变性表现外,还存在轻至中度感音神经性耳聋,测序结果发现家系患者USH2A基因复合杂合突变c.2310_2311insA(p.E771Rfs*8)和c.8559-2A>G(IVS42),而在与患者有直系血缘关系的亲属中发现仅存在其中1个突变,其他家属成员和正常人中未发现该两种突变。

结论：USH2A基因为该家系的致病基因,c.8559-2A>G(IVS42)突变为已报道的热点突变,而c.2310_2311insA(p.E771Rfs*8)突变则为首次报道,本研究扩展了USH2A基因导致Usher综合征的突变谱。     

视网膜色素变性和视锥-视杆细胞营养不良患者基因突变频谱分析

目的：分析中国宁夏地区常染色体隐性遗传视网膜色素变性(ARRP)及视锥-视杆细胞营养不良(CORD)的基因突变频谱。

方法：纳入2016-09/2020-02在宁夏人民医院眼科医院就诊的35例ARRP患者和18例常染色体隐性CORD患者,行详细的眼科检查。抽取外周静脉血,对先证者应用包含232个致病基因的遗传性视网膜疾病捕获芯片进行靶向捕获富集高通量测序。利用在线分析软件对可疑基因变异致病性进行预测,利用Sanger测序对家系成员进行共分离分析。

结果：ARRP患者35例中,检测到致病基因16个,以RP1基因突变率最高,占14%(5/35),其次为ABCA4、CRB1和EYS基因,均占11%(4/35); 18例常染色体隐性CORD患者中,检测到致病基因10个,以ABCA4基因突变率最高,占28%(5/18),其次为ALMS1、PROM1、RPE65、USH2A基因,均占11%(2/18); ARRP和CORD患者中,共同致病基因有ABCA4、CLN3、CRB1、PROM1、NRL共5个,占42%(22/53)。

结论：ARRP及CORD两种疾病在表型之间具有一定程度的相似性和交叉性,致病基因突变谱上存在一定重叠性。宁夏地区最常见的重叠基因为ABCA4。     

共同性外斜视家系和散发患者突变基因分析

目的：:报道一个共同性外斜视家系的新发 PAX3基因突变。 方法：:实验研究。选取一个3代6人的共同性外斜视家系,另选择散发患者180例,正常对照组150例。提取家系成员外周血基因组DNA,使用Illumina Hiseq 4000高通量全外显子组测序平台测序,对测序所得数据进行生物信息分析,筛选...     

Identification of two novel compound heterozygous mutations of ADGRV1 in a Chinese family with Usher syndrome type IIC

Background:To describe the clinical and genetic findings in a Chinese family with three sibs diagnosed with Usher syndrome type IIC.

Materials and Methods: Four members received ophthalmic and otologic tests to ascertain the clinical characteristics. According to the clinical phenotype, we focused attention on a total of 658 genes associated with them. We screened the possible pathogenic mutation sites, used Sanger to exclude the false positive and verified whether there were co-segregated among the family members. Results:Typical fundus features found in the proband supported the diagnosis of retinitis pigmentosa (RP). Audiometric test indicated moderate to severe sensorineural hearing impairment while the vestibular function was normal. Whole-exome sequencing identified the presence of two novel compound heterozygous mutations in ADGRV1, a known gene responsible for Usher syndrome type IIC. Mutationc.15008delG/p.Gly5003AlafsTer13 was inherited from the mother while c.18383_18386dupACAG/p.His6130GlnfsTer84 was inherited from the father, and they were co-segregated with the disease phenotype in the family. Conclusions: The mutations found in our study not only broaden the mutation spectrum of ADGRV1, but also provide assistances for future genetic diagnosis and treatment for Usher syndrome patients.     

Novel homozygous loss-of-function mutations in RP1 and RP1L1 genes in retinitis pigmentosa patients

ABSTRACT

Background: Retinitis pigmentosa (RP) is a heterogeneous group of ocular dystrophy. It is challenging to identify the underlying genetic defect in individuals with RP due to huge genetic heterogeneity. This study was designed to delineate the genetic defect(s) underlying RP in extended Saudi families and to describe the possible disease mechanism.

Materials and Methods: Fundus photography and a high definition optical coherence tomography (HD-OCT) were performed in order to detect the earlier stages of macular degeneration. Genomic DNA was extracted followed by genome-wide SNP genotyping and whole exome sequencing (WES). Exome data was filtered to identify the genetic variant(s) of interest.

Results: Clinical examination showed that affected individuals manifest key features of RP. The fundus exam shows pale optic disc and bone spicules at the periphery. OCT shows macular degeneration as early as at the age of 4 years. Whole genome scan by SNPs identified multiple homozygous regions. WES identified a 10 bps novel insertion mutation (c.3544_3545insAGAAAAGCTG; p.Ala1182fs) in the RP1 gene in both affected individuals of family A. Affected individual from family B showed a large insertion of 48 nucleotides in the coding part of the RP1L1 gene (c.3955_3956insGGACTAAAGTAATAGAAGGGCTGCAAGAAGAGAGGGTGCAGTTAGAGG; p.Ala1319fs). Sanger sequencing validates the autosomal recessive inheritance of the mutations.

Conclusion: The results strongly suggest that the insertion mutations in the RP1 and RP1L1 genes are responsible for the retinal phenotype in affected individuals from two families. Heterozygous individuals are asymptomatic carriers. We propose that the protective allele in other homozygous regions in heterozygous carriers contribute to the phenotypic variability in asymptomatic individuals.     

Prevalence of disease-causing mutations in families with autosomal dominant retinitis pigmentosa: a screen of known genes in 200 families

PURPOSE: To survey families with clinical evidence of autosomal dominant retinitis pigmentosa (adRP) for mutations in genes known to cause adRP. METHODS: Two hundred adRP families, drawn from a cohort of more than 400 potential families, were selected by analysis of pedigrees. Minimum criteria for inclusion in the adRP cohort included either evidence of at least three generations of affected individuals or two generations with evidence of male-to-male transmission. Probands from each family were screened for mutations in 13 genes known to cause adRP: CA4, CRX, FSCN2, IMPDH1, NRL, PRPF3 (RP18), PRPF8 (RP13), PRPF31 (RP11), RDS, RHO, ROM1, RP1, and RP9. Families without mutations in autosomal genes and in which an X-linked mode of inheritance could not be excluded were tested for mutations in ORF 15 of X-linked RPGR. Potentially pathogenic variants were evaluated based on a variety of genetic and computational criteria, to confirm or exclude pathogenicity. RESULTS: A total of 82 distinct, rare (nonpolymorphic) variants were detected among the genes tested. Of these, 57 are clearly pathogenic based on multiple criteria, 10 are probably pathogenic, and 15 are probably benign. In the cohort of 200 families, 94 (47%) have one of the clearly pathogenic variants and 10 (5%) have one of the probably pathogenic variants. One family (0.5%) has digenic RDS-ROM1 mutations. Two families (1%) have a pathogenic RPGR mutation, indicating that families with apparent autosomal transmission of RP may actually have X-linked genetic disease. Thus, 107 families (53.5%) have mutations in known genes, leaving 93 whose underlying cause is still unknown. CONCLUSIONS: Together, the known adRP genes account for retinal disease in approximately half of the families in this survey, mostly Americans of European origin. Among the adRP genes, IMPDH1, PRPF8, PRPF31, RDS, RHO, and RP1 each accounts for more than 2% of the total; CRX, PRPF3, and RPGR each accounts for roughly 1%. Disease-causing mutations were not found in CA4, FSCN2, NRL, or RP9. Because some mutations are frequent and some regions are more likely to harbor mutations than others, more than two thirds of the detected mutations can be found by screening less than 10% of the total gene sequences. Among the remaining families, mutations may lie in regions of known genes that were not tested, mutations may not be detectable by PCR-based sequencing, or other loci may be involved.     

Novel CERKL variant in consanguineous Jordanian pedigrees with inherited retinal dystrophies

Objective

To identify the disease-causing variants in 2 families with autosomal recessive inherited retinal dystrophies (IRDs) and to characterize phenotypic variability across the affected family members.

Expression of the TIGR gene in the iris,ciliary body,and trabecular meshwork of the human eye

Purpose: To identify mutations in the rhodopsin ( RHO ) gene in Chinese patients with autosomal dominant retinitis pigmentosa (ADRP) and to measure the prevalence rate of RHO mutations in Chinese ADRP cases. Methods: Thirteen Chinese families with ADRP were clinically characterized. The complete coding region and intron splice sites of RHO were analyzed for mutations with single-strand conformation polymorphism (SSCP) analysis and direct genomic sequencing. Results: One of the 13 Chinese families with ADRP was found to have a new, previously unidentified RHO mutation, a change from GAG to TAG at codon 341. The mutation (E341X) results in an in-frame stop codon, leading to the truncation of the rhodopsin protein. Mutation E341X was not detected in 100 normal control individuals. Patients carrying mutation E341X reported night blindness and showed optic atrophy, vessel attenuation, and a few bone spicule-like pigments in peripheral retina at the age of 23–25 years. At the age of 30 years, visual acuity was severely impaired, peripheral visual field was greatly constricted, rod and cone ERG was not detectable, and only a slight left cone response remained. Conclusion: We have identified a novel rhodopsin mutation (E341X) in a Chinese family with ADRP. The location and character of the mutation expand the spectrum of RHO mutations causing RP. Identification of a RHO mutation in one of the 13 ADRP families studied suggests that only 7.7% of the ADRP cases in a Chinese population were caused by RHO mutations, a ratio significantly lower than that from North America or Europe.