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Leber遗传性视神经病线粒体DNA继发突变位点研究

THE CHARACTERISTICS OF Rb GENE MUTATIONS IN 108 CASES OF RETINOBLASTOMA

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）

A Novel Point Mutation of Kras Gene Coexisted with Codon 12 Mutation

摘要:目的： 检测大肠癌组织中Kras基因的突变情况以指导临床治疗。 方法 ：通过提取15例大肠癌石蜡组织中的DNA并进行PCR扩增,之后采用国际金标准方法直接测序法进行检测获得突变信息。 结果 ：15例大肠癌石蜡组织样本中Kras有4例发生突变,突变率为266%。值得注意的是发现一个新的突变位点密码子42,并且与密码子12突变共存。 结论 ：密码子42的突变进一步证明Kras突变不仅局限于密码子12,13,61,还有与密码子12共存的42位突变。Abstract: Objective: To detect the mutation status of Kras gene in colorectal cancers and to assist the clinical treatments Methods : DNA was extracted from fifteen formalinfixed, paraffinembedded tumor samples of colorectal cancers, and then the fragments containing codons 12,13 and codon 61 were amplified by PCR The sequences were indentified by direct sequencing which is gold standard for the detection of mutation Results : In the 15 samples of colorectal cancer patients, 4 mutations were observed, with 2 in codon 12 and 2 in codon 13 Suprisingly, a novel point mutation at codon 42 of Kras was found, and coexisted with mutation in codon 12 Conclusion : Except for codons 12,13,61 mutation, Kras has other mutation at codon 42 with coexisted with codon 12 point mutation

Primary mutation detection of mitochondrial DNA(mtDNA)in Leber′s hereditary optic neuropathy patients

Optic atrophy,hereditary／diagnosis; Polymerase chain reaction; DNA,mitochondrial; Point　mutation; Sequence analysis

突变特异性引物PCR检测线粒体DNA11778突变

Relation Between BRAFV600E Mutation and Thyroglobulin or Clinicopathologic Characteristics of Papillary Thyroid Carcinoma

ObjectiveTo discuss the correlation of BRAFV600E mutation with clinicopathologic characteristics or thyroglobulin (Tg) in papillary thyroid carcinoma (PTC) and its clinical significance. MethodsThe BRAFV600E mutations of 55 patients with PTC were detected by nested PCR. The relations between BRAFV600E mutation and the clinicopathologic characteristics were analyzed. Results①The BRAFV600E mutations happened in 29 patients with PTC, the mutation rate was 52.7% (29/55).②The BRAFV600E mutation rate was related with extracapsular spread, multiple lesions, regional lymph node metastasis or average Tg value > 1.0μg/L during 2 years after standardized treatment (P value was 0.01, 0.02, 0.02, 0.03, respectively), but which not related with the gender, age, tumor diameter, or TNM stage (P > 0.05). ConclusionThe BRAFV600E mutation in PTC might lead to increased tumor aggressiveness and it might be related with increased Tg value after standardized treatment.

The analysis of mitochondrial DNA point mutation at position 3243 in age-related macular degeneration

Purpose To detect whether a 3243 point mutation existed in age-related macular degeneration (AMD). MethodsTwenty-six cases of wet form AMD patients, ten cases of dry form AMD patients were selected,and compared with twenty nomal controls. After collecting anti-coagulated blood samples, total cellular DNA were extracted and purified. Using polymerase chain reaction and restriction fragment long polymorphism techniques, the mtDNA Ararr;G point mutation at position 3243 were detected. Results After cleaveded by restriction endonuclease Apa I, a 294 bp fragment remained only in all detected DNA samples including twenty-six wet form AMD, and ten dry form AMD. No any other fragment appeared. The result showed that there was no Ararr;G mutation at position 3243 found in AMD. Conclusion It is suggested that mtDNA 3243 point mutation due to maternal inheritance might be not concerned with both wet form AMD and dry form AMD. (Chin J Ocul Fundus Dis,2000,16:231-232)

The major types and clinical manifestations of mitochondrial DNA mutations in Chinese patients with Leber′s hereditary optic neuropathy

Objective To investigate the major types and clinical manifestations of mitochondrial DNA (mtDNA)mutations in Chinese patients with Leber′s hereditary optic neuropathy(LHON). Methods A total of 119 patients with bilateral optic neuropathy from 117 pedigrees, including 37 with determinate diagnosis of LHON(group A) and 82 with suspected LHON(group B),were tested for mtDNA mutations by using single-strand conformational polymorphism, mutation-specific primer polymerase chain reaction and sequencing. Pertinent clinical data and history of the patients with the 11778 mutation were collected. Results Nucleotide positions(np)11778 mutation and np 14484 mutation was found in 33 (89.2%) and 3 (8.1%) patients respectively in group A, while np 11778 mutation was obtained in 26（31.7%）in group B. No 3460 mutation was found in group A or B. The clinical manifestations of 59 patients with np 11778 mutation were as follows: acute or chronic visual loss，no ophthalmalgia, the age of onset of 10-25, and either a central or paracentral scotoma in perimetry. The visual recovery rate was 8.6%～11.6%. Conclusion Chinese patients with LHON have a very high incidence of np 11778 mutation and the clinical manifestations of the patients with np 11778 mutation are similar to those of Caucasian patients. (Chin J Ocul Fundus Dis，2004，20：78-80)

Clinical Significance of Epidermal Growth Factor Receptor Mutations from Patients with Non-Small Cell Lung Cancer

Objective To evaluate the clinical significance of epidermal growth factor receptor EGFR) mutations in the treatment of non-small cell lung cancer ( NSCLC) . Methods Plasma DNAs solated fromblood specimens of 170 NSCLC patients, who were admitted in the First Affiliated Hospital of uangzhou Medical College from December 2005 to December 2007, were subjected to the test of EGFR utant-enriched PCR. The correlation of mutant detection with clinical characteristics was analyzed as well.Results Out of the total 170 patients, EGFR mutations were identified in 77 cases ( 77 /170, 45. 3% ) .EGFR mutations were more frequent in the patients with adenocarcinoma ( P lt; 0. 001) and in the nonsmokers P =0. 001) . In the 33 patients treated with gefitinib, those with mutations ( + ) showed a higher esponse rate and prolonged progression-free survival after the treatment compared with those with mutations( - ) ( P =0. 001 and 0. 001, respectively) . Conclusions EGFR active mutations can be specifically and ensitively detected by EGFR mutant enriched PCR assay. Plasma EGFR mutants detection is valuable in uiding clinical decision.

Search for mutations of the rhodopsin gene in patients with autosomal dominant retinitis pigmentosa

Objective To investigate whether mutations exist in codon 58 and codon 347 of the rhodopsin gene in patients with autosomal dominant retinitis pigmentosa(ADRP)． Methods Point mutations at codons 58 and 347 were detected by restriction endonuclease digestion of exons 1 and 5 amplified by polymerase chain reaction(PCR)．This method was applied to screen genomic DNAs from 57 patients of 38 families with ADRP and 60 normal controls． Results Four patients from one family of ADRP were confirmed to have a point mutation at the second nucleotide of codon 58,and 6 patients from two families of ADRP were found to have a mutation at codon 347．None of these mutations were found in 60 normal subjects． Conclusion It is suggested that molecular genetic heterogeneity exists within ADRP and some subtypes of ADRP are caused by points mutations of the rhodopsin gene． (Chin J Ocul Fundus Dis,1998,14:108-110)