A novel splice site mutation of CRYBA3/A1 gene associated with congenital cataract in a Chinese family

AIM: To identify the disease-causing mutation responsible for the presence of congenital cataract in a Chinese family. METHODS: The study recruited a four-generation Chinese pedigree affected by autosomal dominant congenital cataract (ADCC). Family history and the history of cataract extraction were recorded. Blood samples were collected from individuals for DNA extraction. Direct sequencing of congenital cataract-associated genes was performed. Single-strand conformational polymorphism and bioinformatic analysis were conducted to further study the mutation. RESULTS: Direct sequencing revealed a novel splice site mutation of c.30-2 A>G in the CRYBA3/A1 gene. The mutation co-segregated within all affected individuals in the family and was not found in unaffected members or 100 unrelated normal controls. These results were further confirmed by single-strand conformational polymorphism and bioinformatic analysis using the Human Splicing Finder and MaxEnt online software and Annovar computer software. CONCLUSION: c.30-2 A>G mutation of CRYBA3/A1 gene is a novel mutation and broadens the genetic spectrum of ADCC.     

Identification of a novel FOXL2 mutation in a fourth-generation Chinese family with blepharophimosis-ptosis-epicanthus inversus syndrome

AIM:To characterize the genetic causes and clinical features in a four-generation Chinese family with blepharophimosisptosis-epicanthus inversus syndrome(BPES).METHODS:Thirteen patients with BPES and eight healthy family members were included in this study.All participants received routine ophthalmic examinations.The target next-generation sequencing(NGS)was performed to determine the causative mutation for this family.The silico analysis was also applied to predict the pathogenesis of identified mutations.RESULTS:All patients had severe ptosis,normal intelligence,female patients have normal fertility.Genetic assessments revealed a heterozygous insertion variation in FOXL2 gene,c.672_701 ins GCGGCTGCCGC CGCAGCTGCTG CAGGCGCT(p.Ala234_Gly235 lins AAAAAAAAGA),carried by 13 patient but absent in all unaffected members.In silico analysis supported the pathogenic nature of this highly conserved variant.This mutation resulted in the insertion of 10 amino acids into the encoded polyala nine chain,which increased the number of original polyalanine chains from 14 to 24,resulting in an extended protein.CONCLUSION:A novel FOXL2 mutation c.672_701 ins GCGGCTGCCGCCGCAGCTGCTGC AGGCGCT(p.Ala234_Gly235 lins AAAAAAAAGA)was identified in a large Chinese family with BPES.This study amplified the genotypic spectrum of FOXL2-BPES and better illustrates its genotype-phenotypecorrelations,which provided a basis for elucidating the pathogenesis of BPES and genetic counseling.     

Clinical findings in a patient with Lowe syndrome and a splice site mutation in the OCRL1 gene

The oculo-cerebro-renal syndrome of Lowe (OCRL) is a rare X-chromosomal disorder characterised by the triad of congenital cataracts, renal tubular dysfunction, and mental retardation. Typically complete opacification and discoid deformation of the lenses are seen, indicating a developmental defect in early embryogenesis. We report on a 35-year-old patient with a mild Lowe syndrome phenotype including incomplete lenticular opacities. Clinical findings suggest that the gene product of the mutated allele (IVS19 + 1G > A) identified in the patient exhibits some residual function.     

A novel (Pro79Thr) mutation in the FKHL7 gene in a Japanese family with Axenfeld-Rieger syndrome

PURPOSE: To report the ocular and genetic findings of a Japanese family with Axenfeld-Rieger syndrome associated with a novel Pro79Thr mutation in the FKHL7 gene. METHODS: Observational case series. Genomic DNA of patients from a family with Axenfeld-Rieger syndrome was extracted from leukocytes, and exons of the FKHL7 gene were amplified by polymerase chain reaction for direct sequencing. RESULTS: Molecular genetic analysis disclosed that one Japanese family with Axenfeld-Rieger syndrome had a heterozygous C to A transversion in the first nucleotide at codon 79, designated Pro79Thr mutation in the FKHL7 gene. CONCLUSION: Considering this novel Pro79Thr mutation together with previously reported findings, it is indicated that the clinical features of Axenfeld-Rieger syndrome may depend on the portion of the FKHL7 gene affected by the mutation, although more case reports are needed to clarify genotype-phenotype correlations of the FKHL7 gene.     

A novel mutation of the OPA1 gene in a Japanese family with optic atrophy type 1

PURPOSE: To report a novel mutation of the OPA1 gene in a Japanese family with optic atrophy type 1 (OPA1) and to describe the clinical features of this family. METHODS: Standard ocular examinations were performed on the proband and his two affected sons. The DNA sequence of all exons and splice sites of the OPA1 gene was determined to detect mutations. RESULTS: The proband and his sons had a heterozygous mutation of the OPA1 gene in the third nucleotide of intron 12 (IVS12+3A-->T). Clinically, each patient had reduced visual acuity (onset within the first 6 years of life) and optic nerve pallor. The proband showed bilateral central scotomas and generalized dyschroatopsia. This is the first report of OPA1 gene mutation in Japanese patients with familial optic atrophy. CONCLUSIONS: A mutation of the OPA1 gene was detected in a Japanese family with OPA1, which follows the same pattern as reported in Western countries. It is suggested that mutations of the OPA1 gene contribute to the development of optic nerve atrophy regardless of ethnic groups. Screening for the OPA1 gene mutation will be useful for diagnosis of OPA1 in Japanese patients.     

Identification of a novel mutation in the FGF10 gene in a Chinese family with obvious congenital lacrimal duct dysplasia in lacrimo-auriculo-dento-digital syndrome

AIM: To identify the pathogenic gene variant in a family with lacrimo-auriculo-dento-digital syndrome [LADD (MIM 149730)] showing congenital lacrimal duct dysplasia as the main clinical manifestation and lay the foundation for future research on the pathogenic gene.METHODS: Ophthalmological examinations, including slit-lamp biomicroscopy and lacrimal duct probing, and computed tomography dacryocystography (CT-DCG) were performed for all participants. The family pedigree was drawn, genetic features were analyzed, and the genomic DNA of the subjects was extracted. Pathogenic genes were screened via whole exome sequencing (WES) and confirmed using Sanger sequencing.RESULTS: Six patients belonged to this three-generation family, and their clinical manifestations included congenital nasolacrimal duct obstruction, congenital absence of lacrimal puncta and canaliculi, lacrimal fistulae, and limb deformities. This pattern indicates autosomal dominant inheritance. Diagnosis was based on the clinical characteristics of LADD syndrome, which presented in all the patients in this family. A novel frameshift mutation in the FGF10 gene (NM_004465.1), c.234dupC (p.Trp79Leus*15), was identified in all patients via WES. The variant was confirmed by Sanger sequencing and classified as a “pathogenic mutation” according to the American College of Medical Genetics and Genomics (ACMG) variant interpretation guidelines.CONCLUSION: A novel frameshift mutation in the FGF10 gene is found in all patients. This finding helps this family with LADD syndrome receiving a more accurate clinical diagnosis and genetic counseling by extending the mutation range of the FGF10 gene.     

Autosomal dominant pattern dystrophy: identification of a novel splice site mutation in the peripherin/RDS gene

PURPOSE: To describe the clinical features of and identify the mutation responsible for an autosomal dominant pattern dystrophy occurring in a three-generation family. METHODS: Five affected family members underwent clinical examination and additional testing including intravenous fluorescein angiography where indicated. Mutation screening of the peripherin/RDS gene was performed. RESULTS: Visual acuity ranged from 20/20 to counting fingers. All patients who reported vision loss noted the onset after the age of 40 years. Predominantly perifoveal, discrete, retinal pigment epithelial changes were present in all patients. Two patients had extensive peripheral yellowish flecks, and one had an atrophic macular scar. Mutation screening of the complete peripherin/RDS coding sequence and exon/intron boundaries revealed a novel splice site mutation. CONCLUSION: A three-generation family with an autosomal dominant pattern dystrophy arising from a previously unreported splice site mutation in the RDS gene is described.     

FBN1基因新突变导致常染色体显性遗传眼病晶状体脱位一家系三例分析

目的 通过对一汉族晶状体脱位家系3名患病成员的原纤维蛋白-1（FBN1）基因突变分析,追踪观察眼睛、心血管及全身临床表现,分析FBN1基因突变与临床表型关系。方法 系列病例研究。收集该家系所有成员的眼与心血管系统等全身临床资料。采用聚合酶链式反应和直接测序法对该家系所有成员进行FBN1基因的突变检测。结果 研究发现3名晶状体脱位患者均携带FBN1基因一个新的错义突变（c.1999T>C;p.Cys 515Arg）,而家系中正常个体无此变异。SIFT和PolyPhen-2生物信息学分析数据高度支持该变异为致病性突变。家系中3名患者均存在不同程度的晶状体脱位,1名年长患者还伴有主动脉瘤样扩张。结论 FBN1基因c.1999T>C的突变可导致常染色体显性遗传眼病晶状体脱位。家系患者的的临床表现存在异质性,年轻患者是否可确诊为马凡综合征还需长期追踪观察。     

家族性渗出性玻璃体视网膜病变致病基因 FZD4变异位点的遗传学研究

目的筛查一个家族性渗出性玻璃体视网膜病变(FEVR)致病基因变异的突变位点。 方法2019年7月收集常染色体显性遗传FEVR家系三代6例的临床资料。采集家系中2例FEVR患者和2位眼正常者的外周血样本。利用二代高通量基因测序技术及Sanger测序对4位受检者的20 000个基因进行测序分析，比较分析眼科疾病相关基因，明确该家系致病基因的突变位点。 结果本家系的先证者，女性，15岁，右眼最佳矫正视力为0.6，左眼最佳矫正视力为0.5。眼底检查结果显示视网膜周边部血管分支多，呈"柳枝"样形态，荧光素眼底造影可见无血管区。患儿四肢修长，身材高大，全身患有二尖瓣和三尖瓣关闭不全，疑似Loeys-Dietz综合征。先证者父亲右眼最佳矫正视力为0.2，左眼最佳矫正视力为0.5，曾行双眼激光治疗，眼底显示有FEVR改变。其余家族成员中，先证者祖父母可见晶状体混浊，眼底检查未见异常；先证者母亲和姑母，视力良好，眼前节及眼底检查均未见异常。家系中4位受检者周围血的遗传基因检测结果显示，先证者及其父亲2例FEVR患者携带基因/转录本FZD4/NM_012193.3核苷酸杂合变异c.1498delA，氨基酸变异p.Thr500fs，该变异导致第500位氨基酸由苏氨酸突变为亮氨酸，可致后续蛋白翻译发生提前终止，产生截断蛋白。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，该变异被评定为疑似致病性变异，2位眼正常人未检测出该基因变异。4位受检者中发现先证者及其母亲携带基因/转录本转化生长因子β2(TGFβ2)/NM_001135599.3核苷酸杂合变异c.673G>A，氨基酸变异p.Glu225Lys，该变异点为临床意义不明变异，可能与Loeys-Dietz综合征相关。 结论FZD4基因核苷酸变异c.1498delA(p.Thr500fs)属于基因位点变异，该变异可以解释此FEVR家系的致病原因。FZD4和TGFβ2基因突变可以共存于一个个体。     

Identification of a stop codon mutation in exon 2 of the collagen 2A1 gene in a large stickler syndrome family

PURPOSE: To describe the clinical features and identify the mutation responsible for an autosomal dominant vitreoretinal degeneration occurring in a previously unreported large family. DESIGN: Cohort study. METHODS: Family members were evaluated clinically over a 30-year period. Genealogical investigation, genetic linkage to known vitreoretinal degenerations, and mutation screening of the COL2A1 gene were performed. RESULTS: We identified a single large family (2,384 total family members) with vitreoretinal degeneration spanning 12 generations. We reviewed the clinical records of 165 family members (95 affected and 70 unaffected). The common clinical findings in affected individuals included early-onset posterior perivascular retinal degeneration, vitreous degeneration, and retinal detachment. The incidence of retinal detachment was 57% (95/165) and the mean age of onset was 15.2 years. Orofacial, skeletal, and auditory abnormalities were seen in 0%, 5%, and 7.5%, respectively, in a subset of 28 affected subjects. Linkage to the collagen COL2A1 locus was demonstrated and a cytosine to adenosine transition identified within exon 2, leading to the creation of a stop codon at position 86 (Cys86Stop). CONCLUSIONS: Identification of the mutation in this family enables diagnosis of individuals at risk for potentially blinding complications in this condition at an early age. Given the variability of the Stickler phenotype, mutation detection allows for more comprehensive genetic counseling and directs clinical monitoring to family members inheriting the disease gene.     

De novo insG619 mutation in PAX2 gene in a Japanese patient with papillorenal syndrome

PURPOSE: To describe a Japanese patient with papillorenal syndrome (PRS) and to identify the genetic defect responsible for the disease. DESIGN: Interventional case report. METHODS: Complete ophthalmologic and systemic examinations were performed, and direct genomic sequencing of the PAX2 gene. RESULTS: Fundus examination of a 3-year-old Japanese girl showed atypical coloboma bilaterally. At 6 years of age, she presented with proteinuria, and renal ultrasonography showed hypoplastic kidneys bilaterally. Molecular genetic analysis of the PAX2 gene revealed a de novo heterozygous insertion of a G at position 619. CONCLUSIONS: Our findings suggest that an abnormal development of the optic stalk led to the optic disk dysplasia in PAX2-associated PRS. This indicates that we should consider renal abnormalities when an atypical round coloboma is present. Molecular genetic analysis of the PAX2 gene in combination with renal ultrasonography can help in making an earlier diagnosis of the disease.     

Novel 615delC mutation in the CRX gene in a Japanese family with cone-rod dystrophy

PURPOSE: To characterize the clinical features of a Japanese family with cone-rod dystrophy associated with a novel 615delC mutation in the cone-rod homeobox (CRX) gene. DESIGN: Case reports and results of DNA analysis. METHODS: Mutational screening by direct sequencing was performed for the three exons in the CRX gene. The clinical features were evaluated by visual acuity measurements, electroretinography, and kinetic visual field testing. RESULTS: A 615delC mutation in the CRX gene was identified and found to cosegregate with cone-rod dystrophy. The ophthalmic findings included cone-rod dystrophy with negative-type electroretinograms (ERGs) and a rapid progression after the age of 40 years. CONCLUSION: These findings indicate that the 615delC mutation causes cone-rod dystrophy with a negative-type ERG. The genotype-phenotype correlation in the CRX gene in our patient and others reported in the literature suggest that the negative-type ERG might be a good sign for having a mutation in the CRX gene.     

A novel mutation in the VMD2 gene in an Italian family with Best maculopathy

Vitelliform macular dystrophy (Best disease) is an inherited macular degeneration in which the primary defect is thought to occur at the level of the retinal pigment epithelium. The VMD2 gene, considered responsible for the disease, mapped to the long arm of chromosome 11, and it codifies the bestrophin protein, probably acting as a transmembrane ionic channel. In the present study, we screened for mutations the VMD2 gene in Italian patients with Best maculopathy. Five families with Best disease were recruited from central and southern Italy, and family members were evaluated by complete ophthalmologic examination and DNA analysis by means of DHPLC technology. Some mutations of the VMD2 gene were identified and among them there was a novel mutation (R218G), probably involving a functionally active region of the bestrophin protein. In spite of the small number of families considered, it was possible to note a significant phenotypic heterogeneity. First, in one family the R218C mutation was associated with early onset of choroidal neovascularization (CNV) in the affected mother and her son, while no CNV was reported in another family sharing the same mutation. Then a patient with the R25W mutation showed a multifocal location of the vitelliform deposits, while another family with the same mutation showed a typical isolated vitelliform disc in the macular area.     

A novel mutation of the type 1 optic atrophy(OPA1) gene in a Japanese family with OPA1

PURPOSE: To report a novel mutation of the type1 optic atrophy(OPA1) gene in a Japanese family with OPA1 and to describe the clinical features of this family. METHODS: Standard ocular examinations were performed on the proband and his two affected sons. The DNA sequence of all exons and splice sites of the OPA1 gene was determined to detect mutations. RESULTS: The proband and his sons had a heterozygous mutation of the OPA1 gene in the third nucleotide of intron 12(IVS12 + 3A-->T). Clinically, each patient had reduced visual acuity(onset within the first 6 years of life) and optic nerve pallor. The proband showed a central scotoma and generalized dyschromatopsia. This is the first report of OPA1 gene mutation in Japanese patients with familial optic atrophy. CONCLUSIONS: A mutation of the OPA1 gene was detected in a Japanese family with OPA1, which follows the same pattern as reported in Western countries. It is suggested that mutations of the OPA1 gene contribute to the development of optic nerve atrophy regardless of ethnic groups. Screening for the OPA1 gene mutation will be useful for diagnosis of OPA1 in Japanese patients.