Objective To analyze the relationship between genotype and phenotype of vitelline macular dystrophia (VMD2) gene in a family with Best disease, and to provide the theoretical basis for gene diagnosis of Best disease. Methods Mutation in the coding regions and the promotor sequence of VMD2 gene from 10 members in a family with Best disease were screened by polymerase chain reaction (PCR) and direct DNA sequencing, and combined with a conformation sensitive gel electrophoresis (CSGE) approach, VMD2 gene screening was performed on 100 normal control individuals. Results In the 10 members, Trarr;C nucleotide change at the 223 base of exon 3 was detected in 9, including 6 with Best disease who was confirmed by ophthalmoscopy and electrophysiological examination in whom 2 were affirmed as having homozygote of this mutation. Other 3 young family members with VMD2 gene mutation only had abnormal electro-oculogram manifestations. Above mutation was not detected in the normal control individuals. Conclusions The phenotype and genotype of VMD2 in the family with Best disease is highly correlated. Mutation in VMD2 gene is the nosogenesis in this family. Mutation screening of VMD2 gene can be used for genic diagnosis and genetic consultation of Best disease. (Chin J Ocul Fundus Dis, 2006, 22: 86-89)
Objective To analyze the pathogenesy and mutation of X-linked juvenile retinoschisis (XLRS) 1 gene in XLRS families, and to provide the theory basis in directing gene diagnosis. Methods The mutation of XLRS1 gene code in two XLRS families were detected and screened by polymerase chain reaction (PCR) and DNA direct sequence determination. Results Pro193Ser mutation was detected in family 1. Conclusion Pro193Ser mutation could be found in XLRS families, which can be used for genetic consultation and prenatal gene diagnosis. (Chin J Ocul Fundus Dis，2004，20：149-151)
ObjectiveTo observe the transthyretin (TTR) gene mutation, protein and mRNA expression in patients with familial vitreous amyloidosis. MethodsSubjects were divided into three groups: (1) illness group: seven patients with familial vitreous amyloidosis. (2) No-illness group: 9 unaffected family members. (3) Control group: 9 healthy individuals in same area. Subjects' peripheral venous blood were collected and DNA were extracted, 4 exons of TTR gene were amplified by reverse transcription polymerase chain reaction(RT-PCR), the gene fragments were sequencing by the fluorescence labelling method. Serum TTR protein expression was detected by Western blot, and TTR mRNA in leukocyte was assayed by RT-PCR. Results4 exons of TTR gene of all samples were amplified, and DNA sequencing data showed that 7 patients and 3 subjects DNA from unaffected family members had mutated in the 3rd exon of 107th base, changing from G to C. Heterozygous mutation occurred in codon of the 83th amino acid in exon 3, namely, Gly83Arg, resulted in the change of GGC to CGC. The protein and mRNA expression of TTR was lower in illness group than no-illness group and control groups(P < 0.05). Compared with control group, TTR mRNA expression in unaffected family members groups was significant decreased(P < 0.05). ConclusionHeterozygous mutation occurred in codon of the 83th amino acid in exon 3, namely Gly83Arg, and suggested that Gly83Arg is connected with the change of TTR mRNA and protein expression.
ObjectiveTo report the clinical findings and RS1 gene mutation analysis of a Chinese family with X-linked juvenile retinoschisis (XLRS). MethodsThe pedigree of this XLRS family was studied. Nine individuals (10 eyes of 6 males, 6 eyes of 3 females), including the proband, received ocular examination, fundus photography and optical coherence tomography (OCT). Direct DNA sequencing of the 6 exons of RS1 gene was used to detect the RS1 mutation in 12 family members. ResultsThe present pedigree included 15 members of three generations. Among them, 5 male members were diagnosed with XLRS. The retina of other 4 family members were normal, including 1 male (2 eyes) and 3 females (6 eyes). Visual acuity of these 5 patients ranged from hand movement to 0.5 and both eyes of them were involved. The age when visual acuity begins to decrease was all less than 10 years. Fundus color photographic examination showed macular radial cystoid retinoschisis and retinoschisis of the peripheral retina. OCT images showed retinoschisis in macular regions (8 eyes) or peripheral retina (6 eyes). Genetic testing showed that 1 male had no mutation in RS1 gene (p.Gly109Val). All 5 patients had a point mutation (c.326G>T) at exon 4 of RS1 gene, which cause the 109th amino acid changed from glycine to valine in the RS1 protein. A 3-year-old kid also had this mutation. The 3 females with normal retina had heterozygous mutations of Gly109Val, so they are the mutation carriers. ConclusionThe novel p.Gly109Val mutation is the causing mutation in this Chinese family with X-linked juvenile retinoschisis.
Objective To observe the clinical features, phenotypes and genotypes in a Chinese family with choroideremia (CHM). Methods A Chinese four-generation family (15 members) with CHM, including 5 patients (4 males/1 female), 2 female carriers and 8 healthy members, was enrolled in this study. Initially all family members underwent best corrected visual acuity (BCVA), indirect ophthalmoscopy, fundus fluorescein angiography, optical coherence tomography (OCT), visual field and full view electroretinogram (ERG). BCVA was followed up for 3 years. Venous blood samples were collected, and all of the 15 coding exons and flanking intron regions were amplified in the proband by polymerase chain reaction followed by direct sequencing. Protein structure was modeled based on the protein data bank and mutations in DeepView v4.0.1 to predict the effect of the mutations. A total of 180 healthy volunteers were enrolled as control group to matching CHM gene sequences. Results The visual acuity (VA) of 3/4 adult male patients began to decrease at less than 10, 10 and 30 years old, the average BCVA was 0.43. There were characteristic signs and symptoms of CHM including narrow visual field, extinguished rod and cone response in ERG, disappeared junction line and intermediate line of photoreceptor inner segment/outer segment on OCT. After 3 years, the mean BCVA decreased to 0.11. The BCVA of one young male patient was 1.0 in both eyes with minor changes fundus and visual field. The VA of the female patient began to decrease at 50 years old, her BCVA of two eyes were 0.5 and 0.25, respectively. The fundus changes were typical of CHM, with relative scotomas in the peripheral visual field of OD, and big scotomas in the OS. After 3 years, her mean BCVA decreased to 0.2. Of 2 female carriers, one had minor fundus changes (patches of pigmentary deposits, atrophy spots of retinal pigment epithelium cells), and the other was normal. A novel heterozygous c.1837G＞A mutation in exon 15 of CHM was detected in the proband, which resulted in the substitution of serine by proline at codon 613 (p.D613N). Based on molecular modeling, the misfolded protein caused by the mutation might destabilize the structure of the helix that potentially could affect the global stability of the Rep-1 protein. Conclusions A novel c.1837G＞A (p.D613N) mutation may be the causative mutation for CHM in this family. Female CHM carriers may have some signs and symptoms.
Objective To analyze the clinical characteristics and to screen for causative mutations in CRX and GUCY2D genes in children with cone or cone-rod dystrophy. Methods Clinical data and genomic DNA was collected from 18 children with cone or cone-rod dystrophy, aged from 4 months to 8 years. The coding sequence of the cone-rod homeobox (CRX) gene and two exons of the retinal-specific guanylate cyclase GUCY2D gene (exons 2 and 8) were analyzed by using polymerase chain reaction(PCR) and heteroduplex combined with single-strand conformational polymorphism (heteroduplex-SSCP) analysis. Results All of the 18 patients manifested obvious visual impairment. Nystagmus, photophobia and mild ocular fundus changes were found in 13, 8,and 7 cases respectively. Normal fundus was seen in 11 cases. The visual acuity was less than 0.3 in 4 cases and was unable to measure in the other 14 cases because they were too young. Clinical ocular manifestation s between cone and cone-rod dystrophy were overlapped. Mutation in the CRX and G UCY2D genes was not detected in the 18 children with cone and cone-rod dystrophy . Conclusion Visual impairment appeared more early and obvious than fundus changes in children with cone or cone-rod dystrophy. Mutation in the CRX gene may not contribute to this series of patients with cone and cone-rod dystrophy. (Chin J Ocul Fundus Dis, 2001,17:293-295)
Objective To observe the gene mutation and clinical phenotype of patients with retinitis pigmentosa (RP) and cone rod dystrophy (CORD). Methods Thirty-seven patients with RP and 6 patients with CORD and 95 family members were enrolled in the study. The patient’s medical history and family history were collected. All the patients and family members received complete ophthalmic examinations to determine the phenotype, including best corrected visual acuity, slit lamp microscope, indirect ophthalmoscopy, color fundus photography, optical coherence tomography, full-field electroretinogram, and fluorescein fundus angiography. DNA was abstracted from patients and family members. Using target region capture sequencing combined with next-generation sequencing to screen the 232 candidate pathogenic mutations. Polymerase chain reaction and direct sequencing were used to confirm the pathogenic pathogenic mutations and Co-segregation is performed among members in the family to determine pathogenic mutation sites. The relationship between genotype and clinical phenotype of RP and CORD was analyzed. Results Of the 37 patients with RP, 13 were from 6 families, including 4 families with autosomal dominant inheritance, 2 families with autosomal recessive inheritance, and 3 in 6 families were detected pathogenic gene mutations. 24 cases were scattered RP. Six patients with CORD were from four families, all of which were autosomal recessive. Of the 43 patients, 21 patients were detected the pathogenic gene mutation, and the positive rate was 48.8%. Among them, 15 patients with RP were detected 10 pathogenic gene mutations including USH2A, RP1, MYO7A, C8orf37, RPGR, SNRNP200, CRX, PRPF31, C2orf71, IMPDH1, and the clinical phenotype included 10 typical RP, 2 cases of RPSP, 3 cases of Usher syndrome type 2 and 6 cases of CORD patients were all detected pathogenic gene mutations, including 2 cases of ABCA4, 2 mutations of RIMS1 gene, 1 case of CLN3 gene mutation, and 1 case of CRB1 and RPGR double gene mutation. Conclusions RP and CORD are clinically diverse in genotype and clinically phenotypically similar. For patients with early RP and CORD, clinical phenotype combined with genetic analysis is required to determine the diagnosis of RP and CORD.
Autosomal recessive Best disease (ARB) is a rare clinical fundus disease caused by BEST1 mutation. The critical features of ARB are the presence of multifocal subretinal yellowish lesions, which corresponding to the hyperfluorescent spots on FAF, scattered over the posterior pole of the retina, absent of typical vitelliform lesions in the macula. Imaging of OCT is often manifested as subretinal or intraretinal fluid, and cystoid macular edema, and hypereflective focus at RPE level. EOG shows an absent or severely reduced light rise (decreased value of Arden), which often accompanied by reduction and delay of the rod and cone ERG. Some patients with ARB show hyperopia, short axial length and shallow anterior chambers, with a corresponding high incidence of angle-closure glaucoma. Though there isn't any effective therapeutic methods of ARB at present, prevention and treatment for its complications such as angle-closure glaucoma and choroidal neovascularization should be considered. Present study about ARB mainly focus on some retrospective cases, and ARB is often misdiagnosed with Best vitelliform macular dystrophy, central serous chorioretinopathy and other fundus diseases in clinic. A detailed understanding of the clinical features and genetic characteristics of ARB might be helpful in clinical diagnosis and treatment. Research with larger sample size are expected to further investigate the different stages of ARB and its developing process, the potential pathological mechanism, the relationship between genotype and phenotype, so as to improve the understanding of the disease.