ABSTRACT
Objective:To deeply explore the clinical features and gene mutations of Waardenburg syndrome (WS) by tested of the eyes and genes of three patients.Methods:A Case series study. From 2019 to 2021, 3 children with WS who were diagnosed at Department of Ophthalmology, West China Hospital of Sichuan University were included in the study. Among them, there were 2 males and 1 female; the ages were 3, 4, and 12 months, respectively. All children underwent external eye, anterior segment, fundus and fluorescein fundus angiography, the clinical features of the eyes were observed. The peripheral venous blood of 3 children was collected, and the whole genome DNA was extracted for whole exome sequencing to analyze the gene mutation sites.Results:All children had different degrees of iris heterochromia and fundus pigment abnormalities, and were accompanied by sensorineural hearing impairment. Case 1 had dystopia canthorum; case 2 had macular fovea hypoplasia. The sequencing results of case 1 showed that there were large fragments of heterozygous deletion in exons 2-8 of the Paired box 3 ( PAX3) gene, who was diagnosed as WS Ⅰ type. The sequencing results of of case 2 showed heterozygous mutation in exon 9 of Microphthalmia-associated transcription factor ( MITF) gene (c.1066 C >T), combined with heterozygous mutation in exon 1 of HPS6 gene (c.1417 G> T), who was diagnosed as WS Ⅱ type. The sequencing result of case 3 showed that the exon 3 of SOX10 gene had loss of heterozygosity (c.497_500 delAAGA), who was diagnosed as WS Ⅳ type. Both PAX3 and SOX10 gene mutations were newly discovered mutations. Conclusions:The ocular clinical features of Waardenburg syndrome include hypopigmentation of the iris and choroid, and dystopia canthorum, etc. Early screening of the eye and hearing will help to better diagnose the disease. The large fragments of heterozygous deletion in exons 2-8 of the PAX3 gene, the heterozygous mutation in exon 9 of MITF gene (c.1066 C> T), and the loss of heterozygosity in exon 3 of SOX10 gene are pathogenic genetic variations of 3 children.
ABSTRACT
Background Retinitis pigmeutosa (RP) is a progressive inheritance disease.It is characterized by highly genetical and phenotypical heterogeneity.With the rapid development of genomics,new methods are applied to the genetic screening of RP.Objective This study was to characterize the clinical features of a Chinese family with autosomal RP and to screen the candidate genes.Methods Twelve members from this family were included in the study.All participants underwent complete ophthalmologic examinations.Targeted-capture next generation sequencing (NGS) based molecular genetic analysis was performed on two patients of this RP family(Ⅱ5,Ⅱ 7).The DNA sample from the two patients was separately sequenced using custom capture gene chip,which includes 59 retinal disease genes.The sequencing results were analyzed by bioinformatics technology.Identified variations were verified in the rest family members by PCR and Sanger sequencing.This study was approved by Ethic Committee of West China Hospital,and informed consent was obtained from the subjects.Results Four members of this family were diagnosed as RP,and the rest were asymptomatic.Missense mutation (c.3065T＞C,p.Phe1022Ser) in USH2A and missense mutation (c.1699G＞A,p.Ala1319Gly) in PDE6A were found in two patients (Ⅱ 5 and Ⅱ7).The variants were not co-segregated with the phenotype of this family.The causative mutation was not found by the targeted-capture NGS based eye disease chip,but it ruled out a large number of candidate genes for RP.Conclusions Our study suggests that targeted-capture NGS based eye disease chip can quickly detect mutations in known RP genes.It can be a new applicable and efficient method for molecular genetic analysis of ocular disease.