Objective To observe and analyze the gene mutation and clinical phenotype of patients with cone and rod dystrophy (CORD). MethodsA pedigree investigarion. Two CORD pedigrees including 2 patients and 6 family members were enrolled in Ningxia Eye Hospital of People' Hospital of Ningxia Hui Automous Region for this study. The patients were from 2 unrelated families, all of whom were probands. Take medical history with best-corrected visual acuity (BCVA), color vision, slit lamp microscopy, indirect ophthalmoscopy, fundus color photography, optical coherence tomography (OCT), autofluorescence (AF), fluorescein fundus angiography (FFA), electroretinogram (ERG). The peripheral venous blood of patients and their parents was collected, whole genome DNA was extracted, Trio whole genome exome sequencing was performed, Sanger verification and pedigree co-segregation were performed for suspected pathogenic mutation sites. According to the law of inheritance, family history was analyzed to establish its genetic type. Mutational loci pathogenicity was analyzed according to the American College of Medical Genetics (ACMG) guidelines and 4 online tools. ResultsTwo CORD families showed autosomal recessive inheritance. The proband of pedigree 1 was female, 49 years old. Binocular vision loss with photophobia lasted for 9 years and night blindness for 4 years. The BCVA of right eye and left eye were 0.03 and 0.06, respectively. The results of ERG showed that the amplitudes of dark adaptation 0.01 b-wave and dark adaptation 3.0 a-wave and b-wave in both eyes were slightly decreased, and the amplitudes of light adaptation 3.0 a-wave and b-wave were severely decreased. The proband of pedigree 2 was male, 30 years old. Vision loss in both eyes for 4 years. Denying a history of night blindness. The BCVA of right eye and left eye were 0.3 and 0.2, respectively. The results of ERG showed that the amplitudes of dark adaptation 0.01 b-wave and dark adaptation 3.0 a-wave and b-wave in both eyes were slightly decreased, and the amplitudes of light adaptation 3.0 a-wave and b-wave were severely decreased. The color of optic disc in both eyes was light red, the macular area was atrophic, the foveal reflection disappeared, and the peripheral retina was punctate pigmentation. The main fundus changes in 2 patients were macular atrophy. The proband of pedigree 1 carried compound heterozygous variations c.439-2A>G (M1) and c.676delT (p.F226fs) (M2) on CDHR1 gene. Her father and mother carried M2 and M1 heterozygous mutations, respectively. The proband of pedigree 2 carried compound heterozygous variations c.2665dupC (p.L889fs) (M3) and c.878T>C (p.L293P) (M4) on C2orf71 gene. His father and mother carried M4 and M3 heterozygous mutations, respectively. According to ACMG guidelines and on line tools, 4 variations were considered as pathogenic level. ConclusionsM1 and M2 of CDHR1 gene and M3 and M4 of C2orf71 gene are new pathogenic mutations of CORD. All patients presented with the clinical phenotype of decreased visual acuity and macular atrophy.
Objective To screen and analyze NR2E3 gene mutations in rentinitis pigmentosa (RP) patients from Ningxia area of China. Method 120 RP patients were enrolled in this study. The patients include 33 autosomal dominant RP (ADRP) patients from 18 families, 20 autosomal recessive RP (ARRP) patients from 15 families, and 67 simplex RP (SRP) patients.100 healthy people were collected as the control group. PCR and direct DNA sequencing were used to screen the entire coding region and splice sites of NR2E3 gene. Multiple analysis was used to study the effects of NR2E3 gene on RP. ResultsA total of 12 different sequence variants in the NR2E3 gene were identified, including 6 novel sequence variants. 5 variants were detected in non-coding regions; 7 variants were detected on the 4th, 6th, 7th exon which including 3 synonymous mutations and 4 missense mutations. All of them were NR2E3 gene polymorphisms and showed no positive correlation with the RP confirmed by the multivariate logistic regression analysis. The missense mutation of p.Glu121Lys was first found in 1 ADRP proband, 2 SRP patients and 2 control subjects. Among other 8 affected individuals in this ADRP family, 5 patients also had the p.Glu121Lys variant. Notably, the 6 affected individuals with p.Glu121Lys showed more serious ophthalmic findings (early onset and early central visual impairment) than other 3 affected individuals without p.Glu121Lys.Conclusion The mutation frequency of NR2E3 and p.Glu121Lys variant in NR2E3 gene in Ningxia RP patients were lower than previous reports in other populations.
ObjectiveTo identify 3 the disease-causing genes and mutations of Leber congenital amaurosis (LCA), and to study the correlation of phenotype and genotype. MethodsA 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. ResultsOf 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. ConclusionsPRPH2 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.