Objective To analyze the relationship between genotype and phenotype in 3 pedigrees with Stargardt disease.Methods Three pedigrees with Stargardt disease were included in Ningxia Eye Hospital from January 2017 to September 2017.The clinical features of patients and other family members were evaluated by ophthalmic examinations,including visual acuity,best corrected visual acuity (BCVA),fundus examination,optical coherence tomography (OCT),fundus fluorescein angiography (FFA) and electroretinogram (ERG).The periphery blood sample of 5 ml from patients and 1 family member with normal phonotye in each family were collected.The next generation sequencing,PCR and direct sequencing were used to confirm the disease-causing mutation.The relationship between genotype and phenotype was analyzed.This study was approved by Ethic Committee of Ningxia Eye Hospital and informed consent was obtained from each subject.Results In 3 Stargardt pedigrees,2 pedigrees showed autosomal recessive inheritance,and 1 pedigree was pseudodominant inheritance.Five mutations on ABCA4 gene were detected and p.F2188S and p.Y345C were novel muations.All pedigrees carried two heterozygous mutation.The onset age of the patients were adolescence except just one patient who suffered at the age of 50 years old.The visual acuity was severely affected and the OCT indicated different degrees of macular atrophy.The results of the ocular fundus photography and the FFA were variable.Conclusions The patients with stargardt disease often carry heterozygous mutation on ABCA4 gene and available characteristics,including early onset age,varying ocular fundus and severe visual impairment.Next generation sequencing technique shows the advantages of rapid and high efficiency in the diagnosis of Stargardt disease.

Background Hereditary retinal diseases (HRDs) are a group of retinal degenerative diseases with significant genetic and clinical heterogeneities.Traditional techniques are challenging for detection of pathogenic mutations.Objective This study was to identify the diseasing-causal genes in 20 Chinese families with a variety of HRDs.Methods Family histories and ophthalmic examinations were obtained from all participants in 20 sporadic families.Targeted sequence capture array technique with next-generation sequencing (NGS) was performed to detect pathogenic mutations in 232 identified genes associated with HRDs.Variants detected by NGS were filtered by bioinformatic analysis HRDs.Genotype-phenotype correlation was also assessed.Results We identified 11 patients with pathogenic mutations,including 8 compound heterozygous mutations and 3 homozygous mutations,which were not yet reported.These findings showed genetic diagnoses in 11 of 20 patients,with the positive rate of 55％.Among them,6 patients were autosomal recessive inheritance and 5 were unspecific.Identification of different mutations and divergent phenotypes revealed 5 patients were affected with cone-rod dystrophy,3 patients with Leber congenital amaurosis,1 patient with congenital stationary night blindness,1 patient with Best vitelliform macular dystrophy and 1 patient with Stargardt disease.Conclusions Targeted NGS is an effective approach for the genetic diagnoses of HRDs.These findings provide insights into understanding the genotype-phenotype correlations in HRDs.

Objective: To analysis the gene mutation spectrum of retinitis pigmentosa (RP) patients in Ningxia Region of China. Methods: Fifty-five pedigrees and 74 sporadic RP patients were included in Ningxia Eye Hospital from January 2015 to December 2016.Two hundred unrelated healthy adults were enrolled as normal controls during the same period.The clinical features of patients and their family members were evaluated by ophthalmic examinations, including visual acuity, best corrected visual acuity, fundus examination, optical coherence tomography, fundus fluorescein angiography, and visual field and electroretinogram.The next generation sequencing, PCR and direct sequencing were used to confirm the pathogenic mutation.This study was approved by Ethic Committee of the Ningxia Eye Hospital (NO.20150107), and informed consent was obtained from each subject. Results: The mutations were detected in 37 RP pedigrees, 8 pedigrees showed autosomal dominant inheritance and 6 pathogenic genes were confirmed, all the autosomal dominant RP (ADRP) patients carried a single heterozygous mutation.Twenty-five pedigrees were autosomal recessive RP (ARRP) and 12 pathogenic genes were confirmed.Among ARRP patients, the mutations rate of USH2A gene was the highest, accounting for 28% (7/25), EYS gene and MYO7A gene accounted for 12% (3/25). Four X-linked RP (XLRP) pedigrees carried the homozygous mutations on RPGR gene.Twenty-five disease-causing genes were detected in 49 sporadic RP patients.The mutation rate of USH2A gene was the highest, accounting for 26.5% (13/49), followed by RP1 gene, accounting for 8.1% (4/49). Conclusions Recessive inheritance is the most common cause of RP.USH2A gene is the main pathogenic gene of RP in Ningxia region of China.

Objective:To identify 3 the disease-causing genes and mutations of Leber congenital amaurosis (LCA), and to study the correlation of phenotype and genotype.Methods:A retrospective study. Four LCA patients and seven family members who were diagnosed by eye examination in Ning Xia Eye Hospital of People's Hospital of Ningxia Hui Autonomous Region from January to December 2021 were included in the study. Four patients were from 3 unrelated families. Detailed collection of medical history and family history were received. Related ophthalmologic examination were collected and genomic DNA was extracted from peripheral blood. Whole-exome sequencing method was used for genetic diagnosis. The identified variant was confirmed with Sanger sequencing. Potential pathogenic mutation was analyzed using software and conserved domain analysis and performed co-separated analysis between the family member and the proband.Results:Of the 4 patients, 1 patient was males and 3 patients were females; the age was from 4 to 18 years. Nystagmus were seen in 3 cases, finger pressing eyes and night blindness was seen in 1 cases; electroretinogram showed 4 cases of extinction or near extinction. The foveal reflection was visible in all eyes, and there was no obvious abnormality in the peripheral retina. One eye had strong reflection signal with raised ellipsoid in macular area; two eyes had weak reflection signal faintly visible between retinal layers; 1 eye had increased blood vessel branches, peripheral retinal non-perfusion area with capillary leakage; annular strong autofluorescence in macular area 4 eyes. No obvious abnormality was found in the phenotypes of family members. Genetic testing showed that the proband of pedigree 1 (Ⅱ-1) was found a homozygous missense mutation in c.640A>T (p.C214S) (M1) of PRPH2 gene. The proband of pedigree 2 (Ⅱ-2) was found compound heterozygous mutation in c.1256G>A(p.R419Q) (M2) and c.1A>C (p.M1L) (M3) of TULP1 gene. The proband 3 (Ⅱ-1) and her sister (Ⅱ-2) were both found compound heterozygous mutation in c.1943T>C (p.L648P) (M4) and c.380C>T (p.P127L) (M5) of GUCY2D gene. The parents and sister (Ⅱ-1) of the proband in family 2 and the parents of the proband in family 3 were all carriers of the corresponding heterozygous variant. M1, M3, M4, M5 were novel mutations and unreported. The genotype and disease phenotype were co-segregated within the family. According to the analysis of pedigree and genetic testing results, all 3 families were autosomal recessive inheritance. The amino acid conservation analysis found that M1, M2, M3, M4, and M5 were highly conserved among species. The results of bioinformatics analysis were all pathogenic variants. Conclusions:PRPH2 gene M1, TULP1 gene M3, and GUCY2D gene M4, M5 were novel mutations and not been reported in the literature and database. This research expanded the gene mutation spectrum of LCA. The patients with LCA have available characterristics, including onset age, varying ocular fundus and severe visual impairment.