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

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 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

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 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

OBJECTIVETo illuminate pathogenic gene and mutation in a Chinese family with autosomal dominant retinitis pigmentosa (adRP).

METHODSGenetic linkage analysis was performed on the known genetic loci for adRP with a panel of polymorphic markers, and then all exons including exon-intron boundary, 5oUTR and 3oUTR of the candidate gene were sequenced directly.

RESULTSTwo-point LOD scores were negative with all markers tested except D17S701 (Zmax=2.107, theta=0) and D17S1604 (Zmax=1.806, theta=0). The disease gene locus was confined to RP17 with further genetic linkage and haplotype analysis. Screening all exons including exon-intron boundary, 5oUTR and 3oUTR of carbonic anhydrase 4 (CA4) revealed no mutation in this family.

CONCLUSIONThe disease-causing gene of one Chinese family with adRP was first mapped to RP17, however no gene mutation of CA4 was detected in this family. Maybe there is a complex CA4 gene mutation in this family or a new disease-causing gene for this family in this locus, further study need to be done.

Asian Continental Ancestry Group ; genetics ; Carbonic Anhydrase IV ; genetics ; Exons ; genetics ; Female ; Genetic Linkage ; genetics ; Genetic Markers ; genetics ; Haplotypes ; genetics ; Humans ; Introns ; genetics ; Male ; Mutation ; Retinitis Pigmentosa ; genetics

OBJECTIVETo investigate the frequency and pattern of RP1 point mutations in Chinese retinitis pigmentosa (RP) patients and to examine their effects on the development of RP.

METHODSConformation sensitive gel electrophoresis (CSGE) and direct DNA sequencing were used to determine sequence alterations occurring in the entire coding region of the RP1 gene in 101 Chinese RP patients in Hong Kong.

RESULTSR677X was detected in one RP patient. A nonpathogenic nonsense mutation, R1933X, was identified in three normal individuals and one patient with Stargardt disease. The frequency of RP1 mutations among all RP patients in this study is 1/101. R677X is expected to lead to large disruptions of the encoded protein. Additionally, 10 more missense alterations in the RP1 gene were identified in the subjects of this study. Apart from M479I whose pathogenicity can not be determined currently, other sequence changes are just polymorphisms of the RP1 gene.

CONCLUSIONThe nonpathogenicity of R1933X indicates that the C-terminal 224 residues of RP1 protein may be not critical for RP1. Recently, a C-termnal truncating mutation, Y1053(1 bp del), was reported to occur in an RP patient. Thus RP can be caused by lack of the region of RP1 protein after codon 1052 but before 1933. To confirm such a proposition, a large genotyping study is necessary and is likely to reveal more RP causative mutations and uncover more sequence alterations different from those of other ethnic groups.

Adolescent ; Adult ; Aged ; Child ; China ; DNA ; chemistry ; genetics ; DNA Mutational Analysis ; Eye Proteins ; genetics ; Female ; Gene Frequency ; Genotype ; Humans ; Male ; Middle Aged ; Mutation ; Mutation, Missense ; Retinitis Pigmentosa ; genetics

OBJECTIVETo report a novel mutation in RPGR gene in a Chinese family with X-linked dominant retinitis pigmentosa(XLRP).

METHODSGenetic linkage analysis was performed on the known genetic loci for XLRP with a panel of polymorphic markers, then the mutations were identified by single-strand conformation polymorphism(SSCP) and direct sequencing.

RESULTSSignificant two-point Lod score was generated using marker DXS8025 (Zmax=2.4, theta =0). The disease gene locus was confined to Xp21.1 with further analysis of genetic linkage and haplotype. Mutations screening of RPGR gene in this family revealed a GA deletion at ORF15+483-484 which caused the open reading frameshift. This novel mutation co-segregated with the affected members of the pedigree, but it was not present in the unaffected relatives.

CONCLUSIONThe above finding expands the spectrum of RPGR mutations causing XLRP in Chinese family and is useful for further genetic consultation and genetic diagnosis.

China ; DNA Mutational Analysis ; Eye Proteins ; genetics ; Family Health ; Female ; Genetic Diseases, X-Linked ; genetics ; Humans ; Male ; Mutation ; Pedigree ; Polymorphism, Single-Stranded Conformational ; 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

OBJECTIVETo detect mutation in the rhodopsin gene (RHO) in a Chinese family with autosomal dominant retinitis pigmentosa (ADRP).

METHODSA total of 25 family members from a Chinese family were investigated. All the subjects were examined clinically by direct funduscopy, perimetry and vision test. Evaluation of the proband included electroretinography (ERG). Genomic DNA was extracted using standard method. The complete coding regions of RHO were amplified by polymerase chain reaction (PCR) and the PCR products were subjected to automatic DNA sequencing.

RESULTS512 C>T (P171L), a recurrent missense mutation was detected in the proband. All 12 affected subjects in the family were heterozygous for the mutation. The affected individuals had night blindness at the age of 5-6 years. They had relatively severe impairment of visual acuity and suffered a gradual loss of peripheral visual field at the age of 20-30 years. And they went blind at the age of 40-50 years. Rod and cone ERG were not detectable in the proband.

CONCLUSIONA recurrent missense mutation, 512C>T (P171L), was detected in a Chinese family with ADRP.

Adolescent ; Adult ; Base Sequence ; China ; DNA Mutational Analysis ; Family Health ; Female ; Humans ; Male ; Middle Aged ; Mutation, Missense ; Pedigree ; Polymerase Chain Reaction ; Retinitis Pigmentosa ; genetics ; pathology ; Rhodopsin ; genetics