OBJECTIVE: To explore the genetic basis for a patient with early-onset retinitis pigmentosa (RP). METHODS: A patient who had presented at the West China Hospital of Sichuan University on March 10, 2020 was selected as the study subject. The patient and his parents were subjected to whole exome sequencing (WES). Candidate variants were verified by Sanger sequencing and in silico analysis. RESULTS: The patient has featured substantial loss of binocular vision field. Funduscopy revealed characteristic bone spicule-type pigment deposits, as well as attenuated retinal arterioles and pale-appearing optic discs. WES revealed that he has harbored compound missense variants of a RP-associated CRB1 gene, including c.2969T>C (p.Leu990Ser) and c.1816T>C (p.Cys606Arg), which were respectively inherited from his father and mother. Homozygous c.1816T>C (p.Cys606Arg) variant has been identified among RP patients, whilst the c.2969T>C (p.Leu990Ser) variant was unreported previously. Both variants were predicted as likely pathogenic based on the guidelines from the American College of Medical Genetics and Genomics (ACMG). CONCLUSION The novel compound heterozygous variants of the CRB1 gene probably underlay the early-onset RP in this patient. Above finding has enriched the mutational spectrum of the CRB1 gene.
Male ; Female ; Humans ; China ; Genomics ; Homozygote ; Mothers ; Retinitis Pigmentosa/genetics* ; Eye Proteins/genetics* ; Membrane Proteins/genetics* ; Nerve Tissue Proteins/genetics*

OBJECTIVE: To explore the genetic basis for a Chinese patient with retinitis pigmentosa (RP). METHODS: Whole exome sequencing (WES) was carried out to screen potential variant in the proband. Candidate variants were determined by taking consideration of clinical phenotype. Sanger sequencing was used to verify the variant in the proband and his parents. RESULTS: The proband was found to harbor compound heterozygous variants of c.8G>A (p.Cys3Tyr) and c.958_959insA (p.Arg320Glnfs*29) in the C2ORF71 gene, which has derived from his father and mother, respectively. Both variants were unreported previously. Based on the ACMG guidelines, they were predicted to be likely pathogenic and pathogenic, respectively. CONCLUSION The novel compound heterozygous variants of the C2ORF71 gene probably underlay the pathogenesis of RP in the proband. Above finding has enriched the spectrum of C2ORF71 gene mutations and facilitated genetic counseling for the family.
Asians/genetics* ; China ; Humans ; Mutation ; Pedigree ; Retinitis Pigmentosa/genetics* ; Whole Exome Sequencing

OBJECTIVE: To carry out genetic testing and prenatal diagnosis for a Chinese couple whom had conceived two fetuses featuring multiple malformations including polycystic kidney, polydactyly and encephalocele. METHODS: Following elective abortion, the fetus from the second pregnancy was subjected to whole exome sequencing. Suspected pathogenic variants were verified by Sanger sequencing of the fetus and its parents. RESULTS: The fetus was found to harbor compound heterozygous variants of the CEP290 gene, namely c.2743G>T (p.E915X) and c.2587-2A>T, which were respectively inherited from its father and mother. The same variants were not detected among 100 healthy controls nor reported previously. Bioinformatic analysis suggested both variants to be deleterious. The fetus was diagnosed with Meckel-Gruber syndrome. Prenatal diagnosis for the couple during their next pregnancy suggested that the fetus did not carry the above pathogenic variants. CONCLUSION The compound heterozygous variants of the CEP290 gene probably underlay the pathogenesis of Meckel-Gruber syndrome in the second fetus. Above finding has provided a basis for genetic counseling and prenatal diagnosis for the couple, and also enriched the mutational spectrum of the CEP290 gene.
China ; Ciliary Motility Disorders ; Encephalocele/genetics* ; Female ; Genetic Testing ; Humans ; Pedigree ; Polycystic Kidney Diseases/genetics* ; Pregnancy ; Prenatal Diagnosis ; Retinitis Pigmentosa

OBJECTIVE: To identify the pathogenic mutation underlying retinitis pigmentosa in a large pedigree. METHODS: The pedigree has included three generations showing an autosomal dominant transmission of retinitis pigmentosa. Potential mutations were screened using a retinitis pigmentosa gene panel and an Ion PGM platform. Suspected mutation was verified by Sanger sequencing. RESULTS: A novel heterozygous missense mutation, c.251T>C(p.Leu84Pro), was identified in the RHO gene. The mutation has co-segregated with the retinitis pigmentosa phenotype among all family members and was not found in public databases ExAC, 1000G and dbSNP or 831 healthy controls. The mutation was predicted to be damaging by three major protein-predicting software. CONCLUSION The c.251T>C (p.Leu84Pro) mutation of the RHO gene is a novel pathogenic mutation underlying the retinitis pigmentosa phenotype in this pedigree. Above findings have enabled prenatal diagnosis for the pedigree.
DNA Mutational Analysis ; Eye Proteins ; Humans ; Mutation ; Mutation, Missense ; Pedigree ; Phenotype ; Retinitis Pigmentosa ; genetics

OBJECTIVETo explore the genetic etiology of a pedigree affected with hereditary retinitis pigmentosa.

METHODSHigh-throughput DNA sequencing was used to analyze the sequences of 173 genes associated with hereditary eye diseases in the proband. Suspected mutation was verified with PCR amplification and Sanger sequencing.

RESULTSThe proband was found to have carried a c.570_571 ins GAAGATGCTGT insertional mutation in the RP2 gene located on the X chromosome. All female carriers of the pedigree were heterozygous, while all affected males were hemizygous for the same mutation.

CONCLUSIONThe inheritance pattern of this retinitis pigmentosa pedigree was X-linked recessive. The c.570_571 ins GAAGATGCTGT insertional mutation of the RP2 gene probably underlies the disease.

Eye Proteins ; genetics ; Female ; Genetic Diseases, X-Linked ; genetics ; High-Throughput Nucleotide Sequencing ; Humans ; Intracellular Signaling Peptides and Proteins ; genetics ; Male ; Membrane Proteins ; genetics ; Pedigree ; Pregnancy ; Prenatal Diagnosis ; Retinitis Pigmentosa ; genetics

Retinitis pigmentosa (RP) is a group of inherited disorders which involve photoreceptors of the retina and can lead to visual loss. The genetic and clinical phenotypes of RP feature high heterogeneity. RP can be divided into nonsyndromic and syndromic types, both may feature autosomal dominant, autosomal reccesive and X-linked inheritance. So far, many genes have been identified, most of which are expressed in the photoreceptors or retinal pigment epithelium. Sixty-three genes have been identified in nonsyndromic RP. This paper reviews recent progress in the research of the genetics of RP.
Genes, X-Linked ; Humans ; Proteins ; genetics ; Retinitis Pigmentosa ; genetics

OBJECTIVETo map the gene responsible for a three generations family with autosomal dominant retinitis pigmentosa (ADRP) and screen the mutation in candidate genes.

METHODSFor a 14-member family with 7 suspected patients, systematic and ophthalmic examinations were performed including visual acuity, ophthalmoscopy, perimetry and electrophysiologic test. After the genomic DNA was extracted, genome scanning was performed, and candidate genes were screened for potential mutations.

RESULTSThe maximal two-point LOD score was obtained at D1S252 with a value of 2.02 (θ=0.00), and multi-point LOD score reached its maximum 2.28 at D1S252. However, no mutations were detected in two candidate genes in this region, namely PRPF3 and SEMA4A by direct sequencing.

CONCLUSIONSignificant evidence for linkage was found at the chromosome region of 1p21.1-q23.3. However, neither PRPF3 nor SEMA4A has harbored a mutation. There may exist an additional gene which is responsible for this disease.

Adult ; Aged ; Aged, 80 and over ; Chromosome Mapping ; Female ; Genes, Dominant ; Genetic Linkage ; Genotype ; Humans ; Male ; Microsatellite Repeats ; genetics ; Middle Aged ; Mutation ; Pedigree ; Retinitis Pigmentosa ; genetics ; Young Adult

BACKGROUNDMüller cells in the mammalian retina normally express low levels of glial fibrillary acidic protein (GFAP); however, its expression is upregulated in response to the loss of retinal neurons. The change in expression of GFAP is one of the earliest indicators of retinal damage and is correlated with the time course of disease. The aim of this study was to investigate the time course of degeneration and the expression of GFAP in the retina of mer knockout mice.

METHODSA total of 30 mer knockout mice, aged from 15 - 20 days to 1 year and 32 age-matched wild type mice as controls were tested. Immunohistochemistry was used to show the expression of GFAP in the central and peripheral retina of mer knockout and control mice at postnatal age of 15 days (P15d), 20 days (P20d), 4 weeks (P4w), 6 weeks (P6w), 8 weeks (P8w), 3 months (P3m), 6 months (P6m) and 1 years (P1y).

RESULTSThe expression of GFAP in the central and peripheral retina of wild type mice was limited to the retinal ganglion cell and nerve fiber layers. In the central retina of mer knockout mice, GFAP expression was upregulated at P4w and GFAP immunolabelling penetrates across the entire thickness of the retina at P8w; whereas in the peripheral retina, the GFAP expression was upregulated at P20d and GFAP immunolabelling penetrates the entire retina after P4w.

CONCLUSIONSIncreased expression of GFAP in Müller cells of mer knockout mice occur at P20d in the peripheral retina and P4w in the central retina. GFAP expression in Müller cells appears to be a secondary response to the loss of retinal neurons. Increased expression of GFAP may occur prior to any detectable morphological changes in the retina. This study suggests that the loss of retinal neurons may begin in the early stages of retinitis pigmentosa, prior to the discovery of any morphological changes in the retina.

Animals ; Glial Fibrillary Acidic Protein ; metabolism ; Immunohistochemistry ; Mice ; Mice, Knockout ; Proto-Oncogene Proteins ; genetics ; Receptor Protein-Tyrosine Kinases ; genetics ; Retina ; metabolism ; pathology ; Retinitis Pigmentosa ; genetics ; metabolism ; c-Mer Tyrosine Kinase

BACKGROUNDThe autosomal dominant form of retinitis pigmentosa (ADRP) can be caused by mutations in 14 genes and further loci remains to be identified. This study was intended to identify mutations in a Chinese pedigree with ADRP.

METHODSA large Chinese family with retinitis pigmentosa was collected. The genetic analysis of the family suggested an autosomal dominant pattern. Microsatellite (STR) markers tightly linked to genes known to be responsible for ADRP were selected for linkage analysis. Exons along with adjacent splice junctions of PRPF31 were amplified by polymerase chain reaction (PCR) and screened by direct sequencing.

RESULTSThe caused gene of ADRP was mapped to 19q13.4 between markers D19S572 and D19S877, with a maximum LOD score of 3.01 at marker D19S418 (recombination fraction = 0).

CONCLUSIONThe affected gene linked to the 19q13.4 in a Chinese family with ADRP, which is different from other mutations at the same loci in other Chinese families.

Asian Continental Ancestry Group ; genetics ; Chromosome Mapping ; DNA Mutational Analysis ; Exons ; genetics ; Eye Proteins ; genetics ; Female ; Genotype ; Humans ; Male ; Microsatellite Repeats ; genetics ; Pedigree ; Polymerase Chain Reaction ; Retinitis Pigmentosa ; genetics

OBJECTIVETo map the disease-causing gene in a Chinese family with autosomal dominant retinitis pigmentosa.

METHODSTwenty-seven micro-satellite markers were randomly selected from the region around the known loci of causative genes, and haplotypes were determined by ABI3100 genetic analyzer. Two-point linkage analysis was performed using MLINK.

RESULTSThe Lod score of each marker vs adRP was below 1.

CONCLUSIONThe phenotype of this family may not be caused by mutation of the known disease-causing genes.

Asian Continental Ancestry Group ; genetics ; China ; Female ; Genes, Dominant ; Genetic Linkage ; Genetic Testing ; Humans ; Male ; Microsatellite Repeats ; genetics ; Mutation ; Pedigree ; Phenotype ; Retinitis Pigmentosa ; diagnosis ; genetics ; pathology