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.
Microorganism distributes in the organs of human body which connect with external environment, especially those organs in the gastrointestinal tracts, and it also plays a fundamental role in the physiopathology of the host's body. Because the microorganism is very small and has a great variety, it is difficult to reveal the significance of microorganism in the human physiopathology comprehensively and deeply. With the development of molecular biology, genomics, bioinformatics and other disciplines, the microbiome research will be more possible and easier. There are two key contents of microecology. One of these is to identify and quantify the diversity of microorganism, and the other is to reveal activity and the physiopathological function of microorganism in the host. Microbiome research methods, therefore, can be summarized as the traditional detection methods, construction of gene library, the genetic fingerprint analysis and molecular hybridization techniques and so on.
Purpose To investigate mitochondrial DNA (mt-DNA) mutations in optic neuritis of unknow reason (ONUR) and to assess the pathogenic and differential diagnostic values of screening for mt-DNA mutations in ONUR. Method Thirty patients with ONUR were screened for mt-DNA mutations by using SSCP,mutation-specific primer PCR and sequencing. Results mt-DNA mutations were found in 12 out of the thirty patients.All of the mutations were at 11778 position,but no one at 3460 and 15257. Conclusions Quite a number of patients (12/30,40%) with ONUR were caused actually by mt-DNA mutation．Screening for mt-DNA mutation in these patients has a pathogenic and differential diagnostic significance. (Chin J Ocul Fundus Dis,2000,16:78-79)
ObjectiveTo summarize the correlation between human epidermal growth factor receptor 2 (HER2) gene expression and the efficacy of targeted therapy for patients with HER2-positive breast cancer, and to summarize the new progress in the study of HER2 gene copy number. MethodThe relevant literatures on researches of targeted therapy effectiveness for patients with HER2-positive breast cancer were retrieved and reviewed. ResultsHER2 gene copy number and HER2/centromere on chromosome 17 (CEP17) ratio were related to the prognosis of patients with HER2-positive breast cancer, and circulating tumor DNA sequencing was expected to be a predictive indicator of targeted therapy effectiveness. ConclusionHigher copy number of HER2 gene might be associated with a better prognosis of HER2-positive breast cancer, and HER2/CEP17 ratio and circulating tumour DNA are of some significances in evaluating treatment response of trastuzumab for patients with HER2-positive breast cancer.
The deoxyribonucleic acid (DNA) molecule damage simulations with an atom level geometric model use the traversal algorithm that has the disadvantages of quite time-consuming, slow convergence and high-performance computer requirement. Therefore, this work presents a density-based spatial clustering of applications with noise (DBSCAN) clustering algorithm based on the spatial distributions of energy depositions and hydroxyl radicals (·OH). The algorithm with probability and statistics can quickly get the DNA strand break yields and help to study the variation pattern of the clustered DNA damage. Firstly, we simulated the transportation of protons and secondary particles through the nucleus, as well as the ionization and excitation of water molecules by using Geant4-DNA that is the Monte Carlo simulation toolkit for radiobiology, and got the distributions of energy depositions and hydroxyl radicals. Then we used the damage probability functions to get the spatial distribution dataset of DNA damage points in a simplified geometric model. The DBSCAN clustering algorithm based on damage points density was used to determine the single-strand break (SSB) yield and double-strand break (DSB) yield. Finally, we analyzed the DNA strand break yield variation trend with particle linear energy transfer (LET) and summarized the variation pattern of damage clusters. The simulation results show that the new algorithm has a faster simulation speed than the traversal algorithm and a good precision result. The simulation results have consistency when compared to other experiments and simulations. This work achieves more precise information on clustered DNA damage induced by proton radiation at the molecular level with high speed, so that it provides an essential and powerful research method for the study of radiation biological damage mechanism.
【Abstract】ObjectiveTo review recent studies on Muir-Torre syndrome (MTS) and to improve the knowledge about MTS.MethodsThe literatures in recent years on clinic and gene research of MTS were reviewed.ResultsMTS was is a rare autosomal-dominant disorder characterized by the predisposition to both sebaceous tumors (or multiple keratoacanthomas) and internal malignancies. Gastrointestinal cancers were the most common kind of internal malignancies in MTS patients(61%)，followed by genitourinary cancers(22%). In most cases(56%)，sebaceous tumors appeared after the emergence of internal maliganancy. Both hereditary nonpolyposis colorectal cancer(HNPCC) and MTS were caused by germline mutations in the DNA mismatch repair genes. MTS patients exhibit significantly more mutations in the hMSH2 than in the hMLH1. In these cases , both internal and skin tumors showed the characteristic of high microsatellite instability(MSI).ConclusionThe presence of sebaceous tumors(or multiple keratoacanthomas) necessitates the search for internal malignancies. It is mandatory that patients with MTS, as patients with HNPCC, should be regularly followed up to search new malignancies. Evaluation and monitoring of the family members of patients are also necessary. The patients and their families should be counseled for genetic test. Sequencing the hMSH2 gene should be the prior selection of further examinations when clinical manifestations, history and laboratory tests suggest MTS.
Objective To systematically review the correlation between polymorphism of DNA methyltransferase 1(DNMT1) rs16999593 and the susceptibility of breast cancer. Methods Databases such as PubMed, EMbase, Web of Science, Chinese Biomedical Literature Database, CNKI, WanFang, and VIP database were searched from inception to Mar. 2017 to collect case-control studies on the correlation between DNMT1 rs16999593 C/T polymorphism and the susceptibility of breast cancer. Two reviewers independently identified the literatures according to inclusion and exclusion criterias, extracted data, and assessed the quality of the included studies. The meta-analysis was performed by using RevMan 5.3 software. Results A total of 5 studies involving 1 741 cases and 1 917 control subjects were included. The results of meta-analysis showed that, dominate model ［TT+TC vs. CC: OR=0.63, 95% CI was (0.30, 1.30), P=0.21］, homozygous model ［TT vs. CC: OR=1.01, 95% CI was (0.70, 1.47), P=0.95］, heterozygous model ［TC vs. CC: OR=0.44, 95% CI was (0.18, 1.04), P=0.06］, and additive model ［T vs. C: OR=1.29, 95% CI was (0.90, 1.86), P=0.16］ were not significantly related to breast cancer, but recessive gene model was related to breast cancer ［TT vs. TC+CC: OR=1.74, 95% CI was (1.01, 3.00), P=0.04］. Conclusion The current studies showed that, DNMT1 rs16999593 TT genotype decreases the susceptibility of breast cancer.
ObjectiveTo summarize the application of circulating free DNA (cfDNA) in the diagnosis and treatment of hepatocellular carcinoma (HCC). MethodThe relevant literature on the application of cfDNA in the diagnosis and treatment of HCC both domestic and international was reviewed and summarized. ResultsThe cfDNA is an emerging biomarker in recent years. At present, the different detection methods had been reported in a large number of studies to detect abnormal methylation, hot spot mutation, gene copy number variation, quantitative detection of cfDNA concentration, etc. It was found that the cfDNA could be used in the management process of early diagnosis, treatment guidance, and efficacy evaluation of HCC patients. ConclusionscfDNA detection is a good tool in the diagnosis and treatment of HCC, which can help clinicians make-decisions and bring more possibilities for the diagnosis and treatment of HCC, which is of great significance for changing the current diagnosis and treatment of HCC. However, there are still many challenges in cost control, technology optimization, and standardization of evaluation indicators. With the continuous progress of molecular biology technology and artificial intelligence, the application of cfDNA in diagnosis and treatment of HCC will be further expanded, its advantages will be better played, and the related shortcomings will be gradually solved.
ObjectiveTo explore the presence of common genetic alterations in retinoblastoma and to localize the altered genomic regions.MethodsGenetic instability of chromosome 19, 20, 21, 22 and X of 15 microdissected retinoblastoma tumors were analyzed by the loss of heterozygosity (LOH) and microsatellite instability (MSI).ResultsAmong the 15 patients with retinoblastoma, genome instability ［LOH and(or) MSI］ at one or more loci on the 5 chromosomes in 10 (67%), in which the loss of a single allele was more frequent in chromosomes 19 (33%) and 20 (27%) than in the other 3 chromosomes. Highfrequency LOH between D19S902 and D19S571 suggested gene loci in the 19q13 region might be associated with tumor development in retina. According to the result of MSI, MSI occured at least in one subset of retinoblastoma.ConclusionsOur results provide first evidence of LOH in chromosomes 19 and 20 in retinoblastoma and further support the presence of genome instability in retinoblastoma that may play an important role in the tumorigenesis or progression of retinoblastoma.(Chin J Ocul Fundus Dis, 2005,21:28-31)
Objective To observe the molecular genetic characteristics of seven Chinese families with Leberprime;s hereditary optic neuropathy (LHON). Methods Ophthalmologic examinations were performed on seven probands, maternal members from seven Chinese families and 134 healthy controls. There were two LHON patients in seven Chinese families except probands. The entire mitochondrial genome was amplified using 24 pairs of oligonucleotide primers with overlapping fragments.The mutational site was analyzed through comparison of the Results and Cambridge reference sequence. The penetrance of mutation site was calculated and the haplotype was analyzed. Results Molecular analysis of mitochondrial DNA (mtDNA) in these pedigrees revealed the absence of three common LHON associated with ND4 G11778A, ND1 G3460A and ND6 T14484C mutations. The ND1 T3394C mutation in probands and other matrilineal relatives was present in four out of 134 Chinese healthy controls. Strikingly, these families exhibited very low penetrance of visual impairment. The penetrance was 12.50%, 22.22%, 16.76%, 6.25%, 9.09%, 11.11% and 28.57%. The Results of phylogenetic tree analysis of submitochondrial haplotype showed that these mtDNA polymorphism sites belong to the Asian haplogroups M9, M9, M, D4, M, M9 and M9. Conclusions T3394C mutation exists in seven Chinese LHON pedigrees, and the penetrance was ranged from 6.25% to 28.57%. The patients have different clinical manifestations.