Epigenetic modifications such as DNA methylation, histone post-translational modifications, non-coding RNA are reversible, heritable alterations which are induced by environmental stimuli. Major risk factors of diabetes and diabetic complications including hyperglycemia, oxidative stress and advanced glycation end products, can lead to abnormal epigenetic modifications in retinal vascular endothelial cells and retinal pigment epithelium cells. Epigenetic mechanisms are involved in the pathogenesis of macular edema and neovascularization of diabetic retinopathy (DR), as well as diabetic metabolic memory. The heritable nature of epigenetic marks also playsakey role in familial diabetes mellitus. Further elucidation of epigenetic mechanisms in DR can open the way for the discovery of novel therapeutic targets to prevent DR progression.
ObjectiveTo review the research progress of pathogenesis and genetics of alcohol-induced osteonecrosis of the femoral head (AIONFH). MethodsThe relevant domestic and foreign literature in recent years was extensively reviewed. The pathogenesis, the relationship between gene polymorphism and susceptibility, the related factors of disease progression, and the potential therapeutic targets of AIONFH were summarized. ResultsAIONFH is a refractory orthopedic disease caused by excessive drinking, seriously affecting the daily life of patients due to its high disability rate. The pathogenesis of AIONFH includes lipid metabolism disorder, endothelial dysfunction, bone homeostasis imbalance, and et al. Gene polymorphism and non-coding RNA are also involved. The hematological and molecular changes involved in AIONFH may be used as early diagnostic markers and potential therapeutic targets of the disease. ConclusionThe pathogenesis of AIONFH has not been fully elucidated. Research based on genetics, including gene polymorphism and non-coding RNA, combined with next-generation sequencing technology, may provide directions for future research on the mechanism and discovery of potential therapeutic targets.
Objective To investigate the disease-causing gene of Stargardt disease. Method Fifteen patients with Stargardt disease were analyzed with 11 primers of the 11 exons of ABCR gene by using PCR-SSCP and DNA direct sequencing techniques. Results Three newly detected disease-causing mutations were found. Among those mutations, one is a frameshift mutation and others are single base transition. Conclusion This research confirmed that ABCR gene is associated with Stargardt disease, and 3 new mutations of ABCR gene were found. (Chin J Ocul Fundus Dis,2000,16:240-243)
X-linked retinoschisis (XLRS) is a rare X-linked inherited retinal disorder, caused by mutations in retinoschisin 1 (RS1) gene. Three XLRS mice were established, providing ideal systems to study the mechanism and treatment methods for XLRS. RS1 gene mutations can induce abnormal secretion or adhesion function of RS1 protein. In the past year, phase I clinical trials for XLRS has begun in USA, using adeno associated virus (AAV, AAV8 or AAV2)-mediated gene delivery. With the rapid development of new generation of AAV vector that can transduce more retinal cells through intravitreous delivery, gene therapy for XLRS will have a brighter future.
Inherited retinal degenerations (IRD) are a group of diseases with high genetic heterogeneity and differences in inheritance patterns, age of onset and severity of visual dysfunction. It is one of the leading causes of blindness. In recent years, gene therapy becomes a popular research area in the treatment of genetic diseases due to the rapid development of gene diagnosis technology. Several clinical trials worldwide have proved the safety and effectiveness of gene therapies in IRD. Clinical application of adeno-associated virus -mediated gene therapies for Leber congenital amaurosis and choroideremia clinical trials indicate that patients' retinal functions were improved at different levels after treatment. There are a number of other IRD clinical trials ongoing currently, which bring new possibilities to treat IRD. This article reviews the pathogenesis of IRD, gene vectors and clinical trials in IRD.
Objective To investigate the polymorphism of the vitamin D receptor gene (VDR)TaqⅠin relation to diabetic retinopathy. Method Fragment length discrepant allele specific PCR(FLDAS-PCR) were used to determine VDR genetypes in 158 patients with diabetic retinopathy and in 198 normal subjects. Results The frequency distribution of VDR genotypes in diabetic retinopathy patients was 106 (67.1%) in TT, 33(20.9%) in Tt, 19(12.0%) in tt; and in normal persons was 165 (83.3%) in TT, 23(11.6%) in Tt, 10 (5.1%) in tt. There was a significant difference between diabetic retinopathy patients and normal persons in distribution of VDR gene TaqⅠgenotypes(Plt;0.05). Conclusions There is some distribution alterations of VDR gene polymorphism in diabetic retinopathy patients. (Chin J Ocul Fundus Dis, 2006, 22: 94-96)
ObjectiveTo investigate the association of high density lipoprotein cholesterol (HDL-C) and cholesterol ester transfer protein (CETP) TaqIB mutation with non-arteritic anterior ischemic optic neuropathy (NA-AION) in the Shaanxi Han ethnic population. MethodsThe study cohort consisted of 45 individuals that had been diagnosed with NA-AION and 45 healthy controls (matched for age, gender). None of the cases or controls had a history of diabetes, serious cardio-cerebral vascular diseases, liver and kidney dysfunction that might influence plasma lipid levels. Plasma HDL-C was detected by enzyme-linked immunosorbent one-step, through the Toshiba TBA-40FR automatic biochemical analyzer. CETP TaqIB gene polymorphism was determined by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) techniques for analysis. B2B2 genotype was only a fluorescence band with 535 bp; B1B1 genotype was 2 fluorescence bands with 361, 174 bp; B1B2 genotype was 3 fluorescence bands with 535, 361, 174 bp. The relative risk of genotype, HDL-C and disease occurrence was analyzed by logistics regression analysis. ResultsThere have no significant difference between NA-AION patients and controls about plasma total cholesterol level and triglyceride level (t=1.907, 1.877; P > 0.05). The plasma HDL-C levels were significantly lower in NA-AION patients than in controls (t=2.367, P=0.022). Compared with controls, the prevalence of B1B1 genotype and B1 allele was higher (χ2=17.289, P=0.001), the prevalence of B2 allele (χ2=15.648, P=0.000) was lower in NA-AION patients. The lower concentration of HDL-C was risk factor of NA-AION (odds ratio=6.143, 95% confidence interval 1.262-29.895, χ2=27.676;P=0.013). The proportion of B1B1 genotype was significantly higher in NA-AION patients than in controls (odds ratio=2.24, 95% confidence interval 2.427-36.323, χ2=10.526; P=0.001). ConclusionsThe low plasma HDL-C is independent risk factor for NA-AION and is associated with the development of NA-AION in the Shaanxi Han ethnic population. CETP TaqIB mutation is associated with low plasma HDL-C in NA-AION in the Shaanxi Han ethnic population.
Objective To investigate the relationship between diabetic retinopathy (DR) and insertion/deletion (a/b) polymorphism of a 27 base pair variable number tandem repeat (VNTR) in intron 4 of the endothelial nitric oxide synthase (eNOS) gene. Methods 321 patients of type 2 diabetes mellitus with over 10 years duration (case group) and 146 normal subjects (control group) were enrolled in this study. All the clients are Han Chinese. The case group was divided into DR subgroup (154 patients) and non-DR (NDR) subgroup (167 patients) according to the results of indirect ophthalmoscope and fundus fluorescent angiography. The VNTR polymorphism in eNOS gene was determined by polymerase chain reaction (PCR) combined with 8% agarose gel electrophoresis. Then the b, a allele frequency and b/b, a/a, b/a allele frequency of two groups were compared, and its correlation with diseases were analyzed. Results The b allele frequency of the VNTR in intron 4 of eNOS gene in the DR group was significantly higher than that in the NDR group（chi;2=4.745，P=0.029；OR=1.685，95%CI=1.050-3.905）and control group（chi;2=6.958，P=0.008；OR=1.891，95%CI=1.172-4.437）; b/b allele frequency in the DR group was also significantly higher than that in the NDR group（chi;2=4.811，P=0.028；OR=1.790，95%CI=1.060-4.645）and control group（chi;2= 5.203，P=0.023；OR=1.859，95%CI=1.087-4.952）. Conclusions The b allele and b/b genotype in intron 4 of eNOS gene in the Han Chinese are closely related to DR.
Primary cardiac tumors, which originate from the heart, are uncommon and can be classified as benign or malignant, with the majority being benign. Malignant primary cardiac tumors have a poor prognosis. Benign ones may also cause severe hemodynamic and electrophysiological consequences, but the prognosis is generally good if they are detected early and treated properly. In recent years, researches on the genetic and molecular causes of primary cardiac tumors have yielded some promising breakthroughs, with some of them already being translated into clinical practice. This article reviews research progress and its use in precise diagnosis and targeted therapy from the perspective of DNA, RNA, and protein changes, as well as prospects the promising research directions in the future.
PURPOSE:To investigate the status and detailed structure of Rb gene in primary tumors and somatic cells of patients with retinoblastoma. To identify the character, origin and transmission of oncogenie point mutations. METHODS:DNA hybridization,SSCP analysis and PCR-associated direct sequencing. RESULTS:Among 108 RB patients examined 80 cases were found to have subtle alterations affecting Rb locus,including 44 cases with homozygous Rb point mutations, 20 cases with two independent heterozygous Rb point mutations, 16 cases with heterozygous mutations involved in one allele of Rb gene. Majority of bilateral RB patients and a small fraction of unilateral RB patients were detected to have a germline mutation. In addition the higher frequency of new germline mutation and parental origin of mutation were observed. CONCLUSION :Rb gene is closely associated with retinoblastoma. Two mutation events and resulting inaetivations of both Rb alleles are required for RB tumorigenesis. Based on our own data,the first event is exclusively point mutation. As for the second event,LOH accounts for two third of cases,point mutation for one third of cases. （Chin J Ocul Fundus Dis,1997,13: 12- 16）