De novel heterozygous copy number deletion on 7q31.31-7q31.32 involving TSPAN12 gene with familial exudative vitreoretinopathy in a Chinese family

AIM:To investigate the genetic and clinical characteristics of patients with a large heterozygous copy number deletion on 7q31.31-7q31.32.METHODS:A family with familial exudative vitreoretinopathy(FEVR)phenotype was included in the study.Whole-exome sequencing(WES)was initially used to locate copy number variations(CNVs)on 7q31.31-31.32,but failed to detect the precise breakpoint.The long-read sequencing,Oxford Nanopore sequencing Technology(ONT)was used to get the accurate breakpoint which is verified by quantitative real-time polymerase chain reaction(QPCR)and Sanger Sequencing.RESULTS:The proband,along with her father and younger brother,were found to have a heterozygous 4.5 Mb CNV deletion located on 7q31.31-31.32,which included the FEVRrelated gene TSPAN12.The specific deletion was confirmed as del(7)(q31.31q31.32)chr7:g.119451239_123956818del.The proband exhibited a phase 2A FEVR phenotype,characterized by a falciform retinal fold,macular dragging,and peripheral neovascularization with leaking of fluorescence.These symptoms led to a significant decrease in visual acuity in both eyes.On the other hand,the affected father and younger brother showed a milder phenotype.CONCLUSION:The heterozygous CNV deletion located on 7q31.31-7q31.32 is associated with the FEVR phenotype.The use of long-read sequencing techniques is essential for accurate molecular diagnosis of genetic disorders.

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。

FGFR2 mutation in a Chinese family with unusual Crouzon syndrome

AIM：To describe the clinical characteristics with genetic lesions in a Chinese family with Crouzon syndrome. METHODS： All five patients from this family were included and received comprehensive ophthalmic and systemic examinations.Direct sequencing of the FGFR2 gene was employed for mutation identification.Crystal structure analysis was applied to analyze the structural changes associated with the substitution. RESULTS： All patients presented typical Crouzon features,including short stature,craniosynostosis,mandibular prognathism,shallow orbits with proptosis,and exotropia.Intrafamilial phenotypic diversities were observed.Atrophic optic nerves were exclusively detected in the proband and her son.Cranial magnetic resonance imaging implied a cystic lesion in her sellar and third ventricular regions.A missense mutation,FGFR2 p.Cys342 Trp,was found as disease causative.This substitution would generate conformational changes in the extracellular Ig-III domain of the FGFR-2 protein,thus altering its physical and biological properties.CONCLUSION： We describe the clinical presentations and genotypic lesions in a Chinese family with Crouzon syndrome.The intrafamilial phenotypic varieties in this family suggest that other genetic modifiers may also play a role in the pathogenesis of Crouzon syndrome.

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.

Prevalence and associated factors of corneal blindness in Ningxia in northwest China

AIM:To describe the prevalence and demographic characteristics of corneal blindness in an urban and rural region of Ningxia,located in the northwest part of China.METHODS:A stratified,randomized sampling procedure was employed in the study,including urban and rural area of all age group.Visual acuity,anterior segment and ocular fundus were checked.Related factor of corneal disease,including age,gender,education status,ethnic group,location and occupation,were identified according to uniform customized protocol.An eye was defined to be corneal blindness if the visual acuity was【20/400 due to a corneal disease.RESULTS:Three thousand individuals(1290 from urban area and 1710 from rural area)participated in the investigation,with a response rate of 80.380%.The prevalence of corneal blindness was 0.023%in both eyes and 0.733%in at least one eye.The blindness in at least one eye with varied causes was present in 106participants(3.533%)and in bilateral eyes in 34participants(1.133%).The corneal diseases accounted for 20.754%of blindness in at least one eye and 20.588%of bilateral blindness.The prevalence of corneal disease was higher in older and Han ethnic group,especially those who occupied in agriculture and outdoor work.People with corneal blindness were more likely to be older and lower education.Rural population were more likely to suffer from bilateral corneal blindness than the urban population in≥59-year group(χ2=6.716,P=0.019).Infectious,trauma and immune corneal disease were the three leading causes of corneal disease.Trauma cornealdisease was more likely leading to blindness in one eye.However,infectious and immune corneal diseases make more contribution to the bilateral corneal blindness.CONCLUSION:Corneal blindness is a significant burden of in Ningxia population,encompassing a variety of corneal infections and trauma;the majority of those were avoidable.Health promotion strategies and good hygienic conditions have to be developed.

Identification of a novel p.R1443W mutation in RP1 gene associated with retinitis pigmentosa sine pigmento

AIM:To screen mutations in the retinitis pigmentosa 1(RP1) gene and the rhodopsin(RHO) gene in Chinese patients with retinitis pigmentosa sine pigmento(RPSP)and describe the genotype-phenotype relationship of the mutations.·METHODS:Twenty affected,unrelated Chinese individuals with RPSP(4 autosomal dominant RPSP,12autosomal recessive RPSP and 4 unknown inheritance pattern) were recruited between 2009 and 2012.The clinical features were determined by complete ophthalmologic examinations.Polymerase chain reaction(PCR) and direct DNA sequencing were used to screen the entire coding region and splice junctions of the RP1gene and the RHO gene.The cosegregation analysis and population frequency studies were performed for patients with identified mutations.·RESULTS:Five variants in the RP1 gene and one in the RHO gene were detected in 20 probands.Four missense changes(rs444772,rs446227,rs414352,rs441800) and one non-coding variant(rs56340615) were common SNPs and none of them showed a significant relationship with RPSP.A missense mutation p.R1443W was identified in the RP1 gene in three affected individuals from a family with autosomal dominant RPSP and was found to cosegregate with the phenotype in this family,suggestive of pathogenic.In addition,population frequency analysis showed the p.R1443W mutation was absent in 300 healthy controls.·CONCLUSION:The identification of p.R1443W mutationcosegregating in a family with autosomal dominant RPSP highlights an atypical phenotype of the RP1 gene mutation,while RHO gene is not associated with the pathogenesis of RPSP in this study.To our knowledge,this is the fist mutation identified to associate with RPSP.

Myopia with X-linked retinitis pigmentosa results from a novel gross deletion of RPGR gene

AIM: To identify mutations with whole exome sequencing(WES) in a Chinese X-linked retinitis pigmentosa(XLRP) family. METHODS: Patients received the comprehensive ophthalmic evaluation. Genomic DNA was extracted from peripheral blood and subjected to Sure Select Human All Exon 6+ UTR exon capture kit. The exons were sequenced as 100 base paired reads on Illumina HiS eq2500 system. Only mutations that resulted in a change in amino acid sequence were selected. A pattern of inheritance of the RP family was aligned to identified causal mutation.RESULTS: We analysed the data of WES information from XLRP family. The analysis revealed a hemizygous large genomic deletion of RPGR c.29113 del was responsible for this XLRP. The gross deletion lead to a frame-shift mutation and generate stop codon at 7 animo acid behind Asp(D10 Afs*7), which would serious truncate RPGR protein. The novel frame-shift mutation was found to segregate with retinitis pigmentosa(RP) phenotype in this family. Bilateral myopia was present on the male patients, but carrier female showed unilateral myopia without RP.CONCLUSION: Our study identifies a novel frame-shift mutation of RPGR in a Chinese family, which would expand the spectrum of RPGR mutations. The geno-phenotypic analysis reveals a correlation between RP and myopia. Although exact mechanism of RP related myopia is still unknown, but the novel frame-shift mutation will give our hit on studying the molecular pathogenesis of RP and myopia.