Retinitis pigmentosa (RP) is a group of hereditary blinding fundus diseases caused by abnormalities in photoreceptors of the retina. RP is highly heterogeneous in hereditary and cdinical phenotypes. It can be divided into simple type RP and syndrome type RP. The main inheritance patterns are autosomal dominant, autosomal recessive inheritance and X-linked inheritance. With the popularization and clinical application of gene sequencing technology, more and more disease-causing genes have been discovered, and these genes are mainly expressed in photoreceptor cells and retinal pigment epithelial cell. ln-depth understanding of RP pathogenic genes not only provides a theoretical basis for RP diagnosis and genetic counseling, but also provides guidance for RP gene therapy.
Usher syndrome (USH) is an autosomal recessive hereditary disease, characterized as retinitis pigmentosa and deafness. According to the severity of hearing loss, presence or absence of vestibular dysfunction, Usher syndrome is divided into 3 clinical subtypes: USH1, USH2 and USH3. Due to the genetically heterogeneous, it is important and valuable to find out the gene mutations in USH patients, which will be helpful to prenatal diagnosis, early intervention and gene therapy. Till now, the following 13 USH-related chromosomal loci were reported in the literature: USH1B, USH1C, USH1D (CDH23 gene), USH1F (PCDH15 gene), USH1G (SANS gene), USH1E, USH1H, USH1J and USH1K, USH2A, USH2C, USH2D and USH3 (CLRN1 gene). Ten out of all 13 loci have been located and identified. But more mechanisms should be further investigated, such as the relationship between the locus of gene mutations and clinical symptoms, how the modified protein structures and functions trigger clinical symptoms.
Retinitis pigmentosa (RP) is a disease that seriously affects vision. It mainly affects rod cells and causes night blindness. At the end of the disease, due to the simultaneous involvement of cone cells, the patient’s central vision and peripheral vision loss are not effective. There is no effective treatment method. However, some studies have found that although the function of photoreceptors is lost in the pathological process of RP, the function of bipolar cells and ganglion cells and the neural connection with the visual center are preserved, which provides a condition of therapeutic application in optogenetics for optogenetics. Optogenetics controls the excitability of neurons by expressing the light-sensitive protein represented by rhodopsin ion channel protein-2 on neurons, and has shown great application prospects in reshaping the photoreceptor function of the retina. The treatment of a type of retinal degenerative disease provides an effective treatment option.
ObjectiveTo identify the causative genes of the posterior microphthalmia-retinal pigment degeneration family. MethodsA retrospective clinical study. One child (proband) and 3 family members of a family with posterior microphthalmia-retinitis pigmentosa diagnosed by clinical and genetic examination at Henan Provincial People's Hospital in July 2019 were included in the study. Medical history and family history, and draw pedigree of the patients was collected. Visual acuity, visual field, fundus color photography, optical coherence tomography and electroretinogram (ERG) were examined. The peripheral venous blood of the proband, his parents and sister, and extract the whole genome DNA was collected. Whole-exome sequencing was used to detect genetic variations, the suspected pathogenic variations were verified by Sanger sequencing, and the pathogenicity was determined by bioinformatics analysis. ResultsThe parents discovered the proband was poor vision at the age of 10 months. At the age of 3, the best corrected visual acuity of the right eye and the left eye were 0.3 and 0.4, respectively. No abnormality was found in anterior segment. Extremely high hyperopia in both eyes. The axial length was 14.47 mm and 15.78 mm, respectively. The optic disc of both eyes was relatively small and flushed, retinal folds can be observed in macular area, and no obvious pigment deposition was found. ERG examination showed that the rod system response and the maximal combined response of both eyes decreased slightly to moderately, and the single-flash cone response and the 30 Hz flicker response decreased moderately to severely. Genetic analysis revealed two novel mutations in the membrane frizzled-related protein (MFRP) gene in the proband: c.363delC/p.Thr121Thrfs*16, c.1627C＞T/p .Gln543Stop,37 in exon 4 and 13, the former was a frameshift mutation, encoding 16 amino acids and then terminated, and the latter was an nonsense mutation, truncated 37 amino acids, both which were predicted to be pathogenic and segregate with disease. The mother and sister carried c.363delC, and the father carried c.1627C＞T. ConclusionMFRP gene c.363delC/p.Thr121Thrfs*16, c.1627C＞T/p.Gln543Stop, 37 compound heterozygous mutation may be the pathogenic gene of this family.
Retinitis pigmentosa (RP) is an inherited retinal disease characterized by degeneration of retinal pigment epithelial cells. Precision medicine is a new medical model that applies modern genetic technology, combining living environment, clinical data of patients, molecular imaging technology and bio-information technology to achieve accurate diagnosis and treatment, and establish personalized disease prevention and treatment model. At present, precise diagnosis of RP is mainly based on next-generation sequencing technology and preimplantation genetic diagnosis, while precise therapy is mainly reflected in gene therapy, stem cell transplantation and gene-stem cell therapy. Although the current research on precision medicine for RP has achieved remarkable results, there are still many problems in the application process that is needed close attention. For instance, the current gene therapy cannot completely treat dominant or advanced genetic diseases, the safety of gene editing technology has not been solved, the cells after stem cell transplantation cannot be effectively integrated with the host, gene sequencing has not been fully popularized, and the big data information platform is imperfect. It is believed that with the in-depth research of gene sequencing technology, regenerative medicine and the successful development of clinical trials, the precision medicine for RP will be gradually improved and is expected to be applied to improve the vision of patients with RP in the future.
Objective To observe the characteristics of fundus autofluorescence (AF) in short wavelength AF (SW-AF) and Near Infrared AF (NIR-AF), and their relationship with visual fields. Methods Twelve patients (24 eyes) with primary RP were enrolled in this study. The patients included nine males (18 eyes) and three females (six eyes). The patients aged from 15 to 69 years, with a mean age of (35.33plusmn;15.03) years. All the patients were examined for color photography, SW-AF, NIR-AF, visual fields and optical coherence tomography examination. Results There were hyper-AF ring of varying sizes in posterior pole by SW-AF and NIR-AF examinations. The area of hypo-AF which located in SW-AF hyper-AF ring had a positive correlation with the area of hyper-AF in the NIR-AF (r=0.662，P＜0.05). OCT showed that outside the hyper-AF ring, there were disconnected inner segment/outer segment (IS/OS) junction and external limiting membrane, and thinned outer nuclear layer and retinal pigment epithelium. Peripheral retinal osteocytes-like pigmentation showed non fluorescence in SW-AF and NIR-AF. The plaque-like area showed mottled and low fluorescence examined by SW-AF. SW-AF hyper-AF ring had a positive correlation with visual fields (r=0.492，P＜0.05). Conclusions The area of hypo-AF inside of the SW-AF hyper-AF ring is related to visual fields in RP patients. The retinal structures in the hypo-AF area inside of the SW-AF hyper-AF ring, and in the NIR-AF hyper-AF region are normal.
Cilia are hair-like protuberance on cells of the human body that play a vital role in organs generation and maintenance. Abnormalities of ciliary structure and function affect almost every system of the body, such as the brain, eyes, liver, kidney, bone, reproductive system and so on. Retinal photoreceptor cells are one of sensory neurons which convert light stimuli into neurological responses. This process, called phototransduction, takes place in the outer segments (OS) of rod and cone photoreceptors. OS are specialized sensory cilia, and disruptions in cilia genes, which are causative in a growing number of non-syndromic retinal dystrophies, such as retinitis pigmentosa, Leber’s congenital amaurosis. These syndromes are genetically heterogeneous, involving mutations in a large number of genes. They show considerable clinical and genetic overlap. At present, there are few researches on retinal ciliopathies and clinical treatment strategy. This review shows a comprehensive overview of ciliary dysfunction and visual development related diseases, which contributes to understand the characteristics of these diseases and take early intervention in clinic.
ObjectiveTo observe the changes of circumpapillary retinal nerve fiber layer (CP-RNFL) thickness and optic disk parameters in retinitis pigmentosa (RP) eyes. MethodsProspective clinical case-control study. A total of 25 patients (42 eyes) with RP were in the RP group, and 42 age matched healthy subjects (84 eyes) in the control group. All subjects underwent optical coherence tomography (OCT) examination, in which 37 eyes with 3D optic disk scanning and 5 eyes with circle optic disk scanning. The parameters included average thickness of entire CP-RNFL, thickness of nasal, superior, temporal and inferior quadrant of CP-RNFL, disc area, disc cup area, rim area, cup/disc (C/D) area ratio, C/D horizontal diameter ratio, C/D vertical diameter ratio, disc cup volume and disc rim volume. ResultsThe average thickness and the thickness of temporal and nasal quadrants of CP-RNFL in RP group were significantly thicker than the control group (t=2.27, 3.73, 6.44; P=0.027, 0.00, 0.00), while the thickness of inferior and superior areas were the same as control group(t=-1.49, -1.19; P=0.14, 0.24). The disc area, disc cup area, C/D area ratio, C/D horizontal diameter ratio, C/D vertical diameter ratio, disc cup volume in RP group were significantly bigger than control group (P < 0.05), while rim area and rim volume were not significant differences (t=1.75, 0.40; P=0.08, 0.59). ConclusionIn comparison with the healthy subjects, the average thickness and temporal and nasal areas of CP-RNFL in RP eyes were thicker, and the disc area, disc cup area, C/D area ratio, C/D horizontal diameter ratio, C/D vertical diameter ratio, disc cup volume in RP eyes were bigger.
Objective To detect characteristics and the pathogenesis of rhodopsin (RHO) gene mutation in an inbreeding family with autosomal recessive retinitis pigmentosa (ARRP). Methods Peripheral venous blood 5-8 ml was abstracted from 8 members in the inbreeding ARRP family and 10 control individuals. DNA gene group was picked. Extron 1-5 of RHO gene was amplified by polymerase chain reaction (PCR)，and the mutation of RHO gene was screened by direct DNA sequence measurement. Results The Gln-344-Arg mutation in the RHO gene was detected in 3 patients with ARRP and homozygotes of the mutation in 3 patients were found. Heterozygous of the mutation was detected in the parent of patients and 1 healthy family member. No mutation of RHO gene was found in 2 healthy family members and 10 control individuals. Conclusions The Gln-344-Arg mutation in the RHO gene may be the pathogenic factor of the ARRP family; the frequency of the mutation of RHO gene may increase in the in breeding ARRP family.(Chin J Ocul Fundus Dis，2004，20：145-148)
ObjectiveTo observe and analyze the pathogenic genes and clinical phenotype characteristics of retinitis pigmentosa sinepigmento(RPSP). MethodsA retrospective clinical study. Two patients (proband) and five family members from two RPSP families admitted to Xiamen Eye Center of Xiamen University in December 2022 and Shenzhen Eye Hospital in July 2023 were included in the study. Two families have no blood relationship and were both Han Chinese. Detailed ocular and systemic medical history and specialized examinations were performed for all members, including color fundus photography, fundus autofluorescence (FAF), and full field electroretinogram (ff-ERG) examination. The peripheral venous blood of all members was collected, and genomic DNA was extracted. Pathogenic genes and their loci were screened using whole exome high-throughput sequencing technology. Sanger sequencing was used to verify the pathogenic genes in the two pedigrees. The pathogenicity of candidate variants was evaluated according to the American Society for American College of Medical Genetics and Genomics (ACMG) classification criteria and guidelines for genetic variants. ResultsThe two probands were male, aged 9 and 7 years, respectively. The main complaint was poor binocular vision for 6 and 3 years and poor treatment effect of amblyopia. The proband (Ⅱ2) in family 1 had a pale red color on the optic disc, with leopard-like changes in the posterior pole and thinner retinal arteries. FAF showed mottled fluorescence attenuation outside the macular vascular arch. There was no significant waveform in both bright and dark visual responses of ff-ERG. He also had 6-toed deformity of both feet, renal cysts, and a slightly overweight body. The clinical diagnosis was non-pigmentary retinitis pigmentosa. The proband of family 2 (Ⅱ1) had poor binocular vision in a dark environment and had atrophy lesions on the nasal side of the optic disc and leopard print like changes in the fundus. FAF showed uneven enhancement in the fovea. ff-ERG showed severe abnormalities in dark and light response, with significant decrease and delay in b-wave amplitude and latency. He had no other systemic abnormalities. The clinical diagnosis was binocular RPSP. There were no abnormal ocular and systemic manifestations in the two family members. Gene sequencing revealed a homozygous mutation (c.534+1G>T) of BBS2 gene, which was inherited from the mother and father respectively. Based on clinical manifestations and genetic testing results, the final diagnosis was Bardet Biedl syndrome. The genetic sequencing results confirmed a novel compound heterozygous mutation (c.950T>G: p. Leu317Arg missense mutation and c.849+1G>C splicing mutation) of BBS7 gene. His father (Ⅰ1) and mother (Ⅰ2) carried M1 heterozygous variants. Combined with the clinical manifestations and genetic testing results, the final diagnosis was Bardet-Biedl syndrome (BBS). Family 2 proband (Ⅱ1) carried the BBS7 gene C.950T>G (p.Leu317Arg) (M2) missense variation and C.849 +1G>C (M3) splice site variation. His father (Ⅰ1) and mother (Ⅰ2) carried M3 shear site variation and M2 missense variation, respectively. The two families all fit the autosomal recessive inheritance pattern, and the genotype and clinical phenotype were coseparated. According to ACMG guidelines, M1, M2 and M3 were all identified as possible pathogenic variants. ConclusionsBBS2 gene M1 homozygous variation and BBS7 gene M2, M3 complex heterozygous variation are the possible pathogenic genes in family 1 and family 2, respectively. Two families are affected by BBS and RPSP, respectively.