CDKN1C gene mutation causing familial Silver–Russell syndrome:A case report and review of literature

BACKGROUND Cyclin-dependent kinase inhibitor 1C(CDKN1C)is a cell proliferation inhibitor that regulates the cell cycle and cell growth through G1 cell cycle arrest.CDKN1C mutations can lead to IMAGe syndrome(CDKN1C allele gain-of-function mutations lead to intrauterine growth restriction,metaphyseal dysplasia,adrenal hypoplasia congenital,and genitourinary malformations).We present a Silver-Russell syndrome(SRS)pedigree that was due to a missense mutation affecting the same amino acid position,279,in the CDKN1C gene,resulting in the amino acid substitution p.Arg279His(c.836G>A).The affected family members had an SRS phenotype but did not have limb asymmetry or adrenal insufficiency.The amino acid changes in this specific region were located in a narrow functional region that contained mutations previously associated with IMAGe syndrome.In familial SRS patients,the PCNA region of CDKN1C should be analysed.Adrenal insufficiency should be excluded in all patients with functional CDKN1C variants.CASE SUMMARY We describe the case of an 8-year-old girl who initially presented with short stature.Her height was 91.6 cm,and her weight was 10.2 kg.Physical examination revealed that she had a relatively large head,an inverted triangular face,a protruding forehead,a low ear position,sunken eye sockets,and irregular cracked teeth but no limb asymmetry.Family history:The girl’s mother,greatgrandmother,and grandmother’s brother also had a prominent forehead,triangular face,and severely proportional dwarfism but no limb asymmetry or adrenal insufficiency.Exome sequencing of the girl revealed a new heterozygous CDKN1C(NM_000076.2)c.836G>A mutation,resulting in a variant with a predicted evolutionarily highly conserved arginine substituted by histidine(p.Arg279His).The same causative mutation was found in both the proband’s mother,great-grandmother,and grandmother’s brother,who had similar phenotypes.Thus far,we found an SRS pedigree,which was due to a missense mutation affecting the same amino acid position,279,in the CDKN1C gene,resulting in the amino acid substitution p.Arg279His(c.836G>A).Although the SRS-related CDKN1C mutation is in the IMAGe-related mutation hotspot region[the proliferating cell nuclear antigen(PCNA)domain],no adrenal insufficiency was reported in this SRS pedigree.The reason may be that the location of the genomic mutation and the type of missense mutation determines the phenotype.The proband was treated with recombinant human growth hormone(rhGH).After 1 year of rhGH treatment,the height standard deviation score of the proband increased by 0.93 standard deviation score,and her growth rate was 8.1 cm/year.No adverse reactions,such as abnormal blood glucose,were found.CONCLUSION Functional mutations in CDKN1C can lead to familial SRS without limb asymmetry,and some patients may have glucose abnormalities.In familial SRS patients,the PCNA region of CDKN1C should be analysed.Adrenal insufficiency should be excluded in all patients with functional CDKN1C variants.

Nucleos(t)ide analogues causes HBV S gene mutations and carcinogenesis

BACKGROUND： The long-term use of nudeos（t）ide analogues causes drug resistance and mutations in the HBV reverse tran- scriptase （RT） region of the polymerase gene. The RT region overlaps the HBV surface gene （S gene） and therefore, the mutations in the RT region simultaneously modify S gene sequence. Certain mutations in the RT region bring about truncated S proteins because the corresponding changed S gene encodes a stop codon which results in the loss of a large portion of the C-terminal hydrophobic region of HBV surface protein. The rtA181T/sW172＊, rtM204I/sW196＊ and rtV191I/sW182＊ are the most frequently reported drug-resistant mutations with C-terminal truncation, these mutations have oncogenic potential. DATA SOURCES： PubMed and Web of Science were searched using terms： ＂hepatitis B virus＂, ＂HBV drug resistance mutation＂ ＂HBV surface protein＂ ＂HBV truncation＂, ＂hepatocellular carcinoma＂, ＂rtA181T/sW172＊＂, ＂rtM204I/sW196＊＂, ＂rtV191I/sW182＊＂, and relevant articles published in English in the past decades were reviewed. RESULTS： The rtA181T/sW172＊ and rtV191I/sW182＊ mutants occurred more frequently than the rtM204I/sW196＊ mutant both in chronic hepatitis B patients and the HBV-related hepatocellular carcinoma tissues. Although these mutations occur naturally, nudeos（t）ide analogues therapy is the main driving force. These mutations may exist alone or coexist with other HBV mutations. All these three mutants impair the virion secretion and result in HBV surface protein retention and serum HBV DNA level reduction. These mutations possess potential carcinogenic properties. The three mutations are resistant to more than one nucleos（t）ide analogue and therefore, it is difficult to treat the patients with the truncated mutations.CONCLUSIONS： Nucleos（t）ide analogues induce drug resistance and HBV S gene truncated mutations. These mutations have potential carcinogenesis.

Therapeutic strategies targeting the epidermal growth factor receptor signaling pathway in metastatic colorectal cancer

More than 1.9 million new colorectal cancer(CRC)cases and 935000 deaths were estimated to occur worldwide in 2020,representing about one in ten cancer cases and deaths.Overall,colorectal ranks third in incidence,but second in mortality.More than half of the patients are in advanced stages at diagnosis.Treatment options are complex because of the heterogeneity of the patient population,including different molecular subtypes.Treatments have included conventional fluorouracil-based chemotherapy,targeted therapy,immunotherapy,etc.In recent years,with the development of genetic testing technology,more and more targeted drugs have been applied to the treatment of CRC,which has further prolonged the survival of metastatic CRC patients.

High frequency of the c.3207C>A (p.H1069Q) mutation in ATP7B gene of Lithuanian patients with hepatic presentation of Wilson's disease

AIM： To investigate the prevalence of the ATP7B gene mutation in patients with hepatic presentation of Wilson＇s disease （WD） in Lithuania. METHODS： Eleven unrelated Lithuanian families, including 13 WD patients were tested. Clinically WD diagnosis was established in accordance to the Leipzig scoring system. Genomic DNA was extracted from whole venous blood using a salt precipitation method. Firstly, the semi-nested polymerase chain reaction （PCR） technique was used to detect the c.3207C〉A （p.H1069Q） mutation. Patients not homozygous for the c.3207C〉A （p.H1069Q） mutation were further analyzed. The 21 exons of the WD gene were amplified in a thermal cycler （Biometra T3 Thermocycler, G0ttingen, Germany）. Direct sequencing of the amplified PCR products was performed by cycle sequencing using fluorescent dye terminators in an automatic sequencer （Applied Biosystems, Darmstadt, Germany）. RESULTS： Total of 13 WD patients （mean age 26.4 years; range 17-40; male/female 3/10） presented with hepatic disorders and 16 their first degree relatives （including 12 siblings） were studied. Some of WD patients, in addition to hepatic symptoms, have had extrahepatic disorders （hemolytic anemia 3; Fanconi syndrome 1; neurophsychiatric and behavioural disorder 2）. Liver biopsy specimens were available in all of 13 WD patients （8 had cirrhosis; 1-chronic hepatitis; 3-acute liver failure, 1-1iver steatosis）. Twelve of 13 （92.3%） WD patients had the c.3207C〉A （p.HI069Q） mutation, 6 of them in both chromosomes, 6 were presented as compound heterozygotes with additional c.3472-82delGGTTTAACCAT, c.3402delC, c.3121C〉T （p.RI041W） or unknown mutations. For one patient with liver cirrhosis and psychiatric disorder （Leipzig score 6）, no mutations were found. Out of 16 first degree WD relatives, 11 （68.7%） were heterozygous for the c.3207C〉A （p.H1069Q） mutation. Two patients with fulminant WD died from acute liver failure and ii are in full remission under peniciilamine or zinc acetate treatment. Three women with WD successfully delivered healthy babies. CONCLUSION： The c.3207C〉A （p.HI069Q） missense mutation is the most characteristic mutation for Lithuanian patients with WD. Even 92.3% of WD patients with hepatic presentation of the disease are homozygous or compound heterozygotes for the p.H1069Q mutation.

MitochondrialtRNA^(leu(UUR)) Gene Mutation and the DecreasedActivity of Cytochrom e c Oxidase in Preeclam psia

To explore the roles of mitochondria tRNA leu(UUR) gene mutation at nucleotide 3243 and the activity of cytochrome c oxidase in pathogenesis of preeclampsia, 57 patients with preeclampsia and 60 normotension pregnancy women were screened for tRNA leu(UUR) nt3243 A→G mutation with the method of polymers chain reaction (PCR) and restriction fragment length polymorphism. Cytochrome c oxidase activity was determined by measuring the rate of cyanide sensitive oxidation of reduced cytochrome c using luminosity photographer. The results showed that cytochrome c oxidase activity was significantly lower in the preeclampsia group (0.30±0.39/min, n = 32) than that in the controls (0.73±0.54/min, n = 26, P <0.01). The mitochondria DNA mutation at position 3243 was not found in our series. The results suggested that the decreased activity of cytochrome c oxidase might impair the energy production, leading to the mitochondria dysfunction and placenta dysfunction in preeclampsia patients. Mitochondria dysfunction may be involved in the pathogenesis of preeclampsia. The mutation of mitochondria DNA may not be the common contributor of preeclampsia in our series.

Frequency of primary iron overload and HFE gene mutations (C282Y,H63D and S65C) in chronic liver disease patients in north India

AIM:To identify the frequency of iron overload and study the three mutations in the HFE gene (C282Y,H63D,and S65C) in patients with chronic liver disorders (CLD) and controls. METHODS:To identify patients with iron overload (transferrin saturation > 45% in females and > 50% in males and serum ferritin > 1000 ng/mL) we evaluated 236 patients with CLD,including 59 with non-alcoholic steatohepatitis (NASH),22 with alcoholic liver disease (ALD),19 of cirrhosis due to viruses (HBV,HCV),and 136 with cryptogenic cirrhosis. Mutations of the HFE gene were analyzed by PCR-RE. hundred controls were screened for iron status and the mutations. RESULTS:Seventeen patients with CLD showed evidence of iron overload. Fifteen cases of iron overload had cryptogenic cirrhosis and two had ALD. None of the controls showed iron overload. We did not find any individual with 282Y or 65C either in the cases or in the controls. The prevalence of H63D heterozygosity was 12% in normal individuals,14.8% in 236 patients (16.9% in NASH,13.6% in ALD,26.3% in viral and 12.5% in cryptogenic cirrhosis) and the overall prevalence was 13.98%. Only two of the 17 patients with primary iron overload were heterozygous for H63D. One patient with NASH and one normal individual who were homozygous for H63D showed no iron overload.CONCLUSION:Primary iron overload in Indians is nonHFE type,which is different from that in Europeans and further molecular studies are required to determine the defect in various iron regulatory genes.

Arg124Cys mutation of the TGFBI gene in a Chinese pedigree of Reis-Bücklers corneal dystrophy

AIM: To analyze mutations in transforming growth factor beta-induced (TGFBI) gene in a Chinese pedigree with Reis-Bücklers corneal dystrophy (RBCD,also known as GCD3).METHODS: In a five-generation Chinese family,eight members were identified with RBCD and the rest were unaffected.All members of the family underwent complete ophthalmologic examinations.Exons of TGFBI were amplified by polymerase chain reaction,sequenced,and compared with a reference database.RESULTS: A single heterozygous C>T (R124C) point mutation was found in exon 4 of TGFBI in all the affected members of the pedigree,but not in the unaffected members.CONCLUSION: R124C which was a known mutation for lattice corneal dystrophy type I,segregated with the RBCD in this pedigree.This elucidated the correlation between genotype and phenotype in a Chinese family of RBCD.

Enhanced but hypofunctional osteoclastogenesis in an autosomal dominant osteopetrosis type II case carrying a c.1856C＞T mutation in CLCN7

Type II autosomal dominant osteopetrosis(ADO2), which is the most common form of osteopetrosis, is caused by heterozygous mutations in the chloride channel 7(CLCN7) gene. The osteopetrosis of ADO2 has been attributed to hypofunctional osteoclasts. The mechanism underlying the abnormality in osteoclast function remains largely unknown. This study was designed to investigate gene mutations and osteoclast function in a case that was clinically diagnosed as ADO2. Genomic DNA was extracted from blood samples of this patient, and the 25 exons of CLCN7 were amplified. Peripheral blood from the ADO2 subject and a healthy age- and sex-matched control was used to evaluate osteoclastogenesis, osteoclast morphology, and bone resorption. Analysis of DNA from the patient showed a germline heterozygous missense mutation,c.1856C>T(p.P619L), in exon 20 of CLCN7. A similar homozygous mutation at this site was previously reported in a patient with autosomal recessive osteopetrosis. When cultured, the peripheral blood mononuclear cells(PBMCs) from the ADO2 patient spontaneously differentiated into mature osteoclasts in vitro. The ADO2 patient’s PBMCs formed enhanced, but heterogeneous, osteoclasts in both the presence and absence of macrophage-colony stimulating factor, and nuclear factor-?B ligand. Bone resorption was reduced in the ADO2 patient’s osteoclasts, which exhibited aberrant morphology and abnormal distribution of integrin avβ3. Gene analysis found increased c-fos expression and reduced Rho A and integrin beta 3expression in ADO2 cells. In conclusion, our data suggest that enhanced, heterogeneous osteoclast induction may be an intrinsic characteristic of ADO2.

Anticancer therapeutic strategies for targeting mutant p53-Y220C

The tumor suppressor p53 is a transcription factor with a powerful antitumor activity that is controlled by its negative regulator murine double minute 2(MDM2,also termed HDM2 in humans)through a feedback mechanism.At the same time,TP53 is the most frequently mutated gene in human cancers.Mutant p53 proteins lose wild-type p53 tumor suppression functions but acquire new oncogenic properties,among which are deregulating cell proliferation,increasing chemoresistance,disrupting tissue architecture,and promoting migration,invasion and metastasis as well as several other pro-oncogenic activities.The oncogenic p53 mutation Y220C creates an extended surface crevice in the DNA-binding domain destabilizing p53 and causing its denaturation and aggregation.This cavity accommodates stabilizing small molecules that have therapeutic values.The development of suitable small-molecule stabilizers is one of the therapeutic strategies for reactivating the Y220C mutant protein.In this review,we summarize approaches that target p53-Y220C,including reactivating this mutation with small molecules that bind Y220C to the hydrophobic pocket and developing immunotherapies as the goal for the near future,which target tumor cells that express the p53-Y220C neoantigen.

Novel CYP1B1 mutations and a possible prognostic use for surgical management of congenital glaucoma

AIM: To identify CYP1B1 gene mutations and evaluate their possible role as a prognostic factor for success rates in the surgical management of Egyptian congenital glaucoma patients.METHODS: Totally 42 eyes of 29 primary congenital glaucoma patients were operated on with combined trabeculotomy/trabeculectomy with mitomycin-C and followed up at 1 d, 1 wk, 1, 6 and 12 mo postoperatively. Genomic DNA was extracted from peripheral blood leukocytes. Coding regions of CYP1B1 gene were amplified using 13 pairs of primers, screened for mutations using single-strand conformation polymorphism followed by sequencing of both strands. Efficacy of the operation was graded as either a success [maintaining intraocular pressure(IOP) less than 21 mm Hg with or without antiglaucoma medication], or a failure(IOP more than 21 mm Hg with topical antiglaucoma medications). RESULTS: Seven novel mutations out of a total of 15 different mutations were found in the CYP1B1 genes of 14 patients(48.2%). The presence of CYP1B1 gene mutations did not correlate with the failure of the surgery(P=0.156, odds ratio=3.611, 95%CI, 0.56 to 22.89); while the positive consanguinity strongly correlated with failure of the initial procedure(P=0.016, odds ratio=11.25, 95%CI, 1.57 to 80.30). However, the Kaplan-Meier survival analysis revealed a significantly lower time of IOP control in the subgroup with mutations in CYP1B1 versus the congenital primary glaucoma group without mutations(log rank test, P=0.015).CONCLUSION: Seven new CYP1B1 mutations are identified in Egyptian patients. Patients harboring confirmed mutations suffered from early failure of the initial surgery. CYP1B1 mutations could be considered as a prognostic factor for surgery in primary congenital glaucoma.

基于drop-off ddPCR方法检测急性髓系白血病C-KIT基因N822位点突变及其临床应用

目的:建立急性髓系白血病(acute myeloid leukemia, AML)患者C-KIT基因N822位点突变的drop-off微滴式数字PCR(droplet digital PCR,ddPCR)定量检测方法,并评价其临床应用价值。方法:针对C-KIT基因第17外显子设计一对引物及探针,优化drop-off ddPCR反应条件及体系,评价该方法的特异性、灵敏度、重复性,使用所建立的方法对140例已行Sanger测序的AML初诊患者骨髓标本进行检测,并用二代测序(next generation sequencing, NGS)验证结果;用drop-off ddPCR对3例阳性患者化疗后C-KIT突变频率进行动态监测。结果:drop-off ddPCR检测C-KIT基因N822位点突变的最适退火温度为54℃,空白检测限为1.62拷贝数/μL,最低检测下限为10.12拷贝数/μL,线性良好。140例AML初诊患者样本中Sanger测序检出2例阳性(1.4%),而ddPCR共检出突变7例(5.0%),突变频率为0.29%~7.41%;进一步应用常规NGS方法对ddPCR阳性样本进行验证,共检出阳性3例(2.1%),等位基因频率为1.26%~8.00%。动态监测3例阳性患者C-KIT突变频率,结果显示治疗达完全缓解时C-KIT突变频率明显下降甚至降低至0。结论:本研究建立了检测C-KIT基因N822位点突变的drop-off ddPCR技术,具有良好的方法学检测性能,其灵敏度高于Sanger测序和NGS,有望用于阳性患者缓解后的可检测残留疾病监测及治疗指导。

Reversion Mutation in Dark Variants of Luminous Bacteria and Its Application in Gene Toxicant Monitoring

The luminous intensity of dark variant (S1) separated from photobacterium phosph oreum (A2) was 1/10 000 less than that of wild type. Ethidium bromide (EB) (0.6 mg/L), Mytomycin C (MC, 0.05 mg/L), 2 amino fluorene (2 AF, 1.0 mg/L) all cou ld strongly induce reversion mutation for S1 within 24 h and increase reversion ratio significantly. The results of experiments indicated that these revertants had stable genetic characteristic and the mutation may take place at gene levels . The mutagenesis to S1 caused by EB, MC and 2 AF was detected and it may be us ed as a new rapid, simple and sensitive method for gene toxicant monitoring.

Detection of ATP2C1 Gene Mutation in Familial Benign Chronic Pemphigus

Summary： The ATP2C1 gene mutation in one ease of familial benign chronic pemphigus was investigated.One patient was diagnosed as familial benign chronic pemphigus by pathology, ultrastructral examination and clinical features. Genomic DNA was extracted from blood samples. Mutation of ATP2CI gene was detected by polymerase chain reaction （PCR） and DNA sequencing. The results showed that deletion mutation was detected in ATP2C1 gene in this patient, which was 2374delTTTG. No mutation was found in the family members and normal individuals. It was coneluded that the 2374delTTTG mutation in ATP2C1 gene was the specific mutation for the clinical phenotype for this patient and was a de novo mutation.

MUTATION AND CLINICAL SIGNIFICANCE OF C-FMS ONCOGENE IN HEPATOCELLULAR CARCINOMA

Objective: To study the clinical significance and relationship between c-fms oncogene and hepatocellular carcinogenesis, to further clarify the occurring mechanism of hepatocellular carcinoma (HCC). Methods: PCR-SSCP technique was used to analyse mutation of c-fms oncogene in 30 cases of HCC tissues. Sequencing the PCR products after cloning to prove the mutations, meanwhile the relationship between c-fms mutations and clinical pathology of HCC was investigated. Results: Two abnormal single strands were observed in 10% (3/30) HCC tissues from c-fms DNA corresponding to 301st codon of c-fms amino acids. PCR products of abnormal single strands were sequenced after cloning, it demonstrated that there was transition of T→C at nucleic acid 14855 of c-fms DNA, which corresponded to transition of Leu (TTG)→Ser (TCG) at 301st codon of c-fms amino acids. The mutation was related to malignant degree and type of HCC tissues as well as patient’s age. Conclusion: Mutation of c-fms codon at site 301 implied a molecular mechanism contributing to hepatocellular carcinogenesis.

The relationship between point mutation and abnormal expression of c-fms oncogene in hepatocellular carcinoma

BACKGROUND: Recent research found abnormal expres- sion of the c-fms oncogene, which encodes the macro- phage colony-stimulating factor receptor (CSF-1R), in several human carcinomas including hepatocellular carcino- ma (HCC). But the relationship between the point muta- tion and abnormal expressing of c-fms oncogene in HCC was not clear. This study is to investigate the relationship between point mutation and abnormal expression of c-fms oncogene in hepatocellular carcinoma (HCC) and to clari- fy the mechanism of HCC. METHODS: The expression of c-fms oncogene at different levels of cell, protein and transcription was observed using immune histological ABC, Western blot and Northern blot. PCR-single strand conformation polymorphism and gene sequencing were used to detect the mutation of c-fms in HCC tissues and their surrounding tissues of 30 patients. RESULTS: The expression of c-fms was significantly higher in HCC tissues than in their surrounding tissues (P <0.01). Point mutation of Leu (TTG)—>Ser (TCG) at codon 301 of c-fms amino acids was observed in 21.4% (3/14) HCC tissues. No mutation of c-fms oncogene was detected in the surrounding cancerous tissues. CONCLUSION: Point mutation at codon 301 of c-fms on- cogene is one of the mechanisms of abnormal over-expres- sion in HCC.

基于剩余电流和不平衡电流突变向量比的TN-C-S系统漏电故障检测方法

TN-C-S系统在我国应用广泛,但由于固有剩余电流大,无法区分负荷投切和故障引起的剩余电流变化,漏电总保和中保无法投运,存在安全隐患。针对该问题,提出一种基于剩余电流和不平衡电流突变量之比的漏电故障保护方法。首先,分析剩余电流回路,剩余电流和不平衡电流突变量之比在单相接地故障发生时刻突变,在负荷投切时不变。其次,基于中性线阻抗和接地阻抗不会发生突变的特征,计算故障电流突变量幅值,以故障电流突变量幅值越限作为故障判别依据,实现漏电故障检测。仿真及试验证明,所提方法可有效区分负荷投切和漏电故障,实现大幅值固有剩余电流下的漏电故障检测,在单支路和多支路系统中的检测灵敏度分别为70、150 mA,满足TN-C-S系统多级漏电保护的灵敏度要求。

Hepatitis C virus protease inhibitor-resistance mutations: Our experience and review

Direct-acting antiviral agents(DAAs)for hepatitis C virus(HCV)infection are one of the major advances in its medical treatment.The HCV protease inhibitors boceprevir and telaprevir were the first approved DAAs in the United States,Europe,and Japan.When combined with peginterferon plus ribavirin,these agents increase sustained virologic response rates to70%-80%in treatment-na?ve patients and previoustreatment relapsers with chronic HCV genotype 1 infection.Without peginterferon plus ribavirin,DAA monotherapies increased DAA-resistance mutations.Several new DAAs for HCV are now in clinical development and are likely to be approved in the near future.However,it has been reported that the use of these drugs also led to the emergence of DAA-resistance mutations in certain cases.Furthermore,these mutations exhibit cross-resistance to multiple drugs.The prevalence of DAA-resistance mutations in HCV-infected patients who were not treated with DAAs is unknown,and it is as yet uncertain whether such variants are sensitive to DAAs.We performed a population sequence analysis to assess the frequency of such variants in the sera of HCV genotype 1-infected patients not treated with HCV protease inhibitors.Here,we reviewed the literature on resistance variants of HCV protease inhibitors in treatment na?ve patients with chronic HCV genotype 1,as well as our experience.

猪瘟病毒C株表位突变毒株的构建及拯救

本研究旨在突变猪瘟病毒C株WH303位点,构建感染性克隆,为猪瘟病毒C株标记疫苗的研究提供候选毒株。本试验以猪瘟病毒C株为研究材料,经重叠PCR方法突变WH303位点,再分别连接至C株和C-flag株全长感染性克隆。体外转录RNA,转染PK15细胞,细胞连续传代完成病毒的拯救和增殖。结果显示,经特异性限制内切酶酶切反应验证,感染性克隆构建成功。经RT-PCR、过氧化物酶单层细胞试验检测,表明病毒成功拯救。病毒细胞传代至17代,检测到病毒,表明病毒可以稳定传代。综上,本研究成功构建了C株WH303突变感染性克隆MC和MC-flag,并成功拯救MC株,得到可以稳定传代的病毒株。

A mutation of the start codon in the X region of hepatitis B virus DNA in a patient with non-B,non-C chronic hepatitis

There are cases of hepatitis involving occult hepatitis B virus(HBV)infection in which,even though the HB surface antigen(HBsAg)is negative,HBV-DNA is detected by a polymerase chain reaction(PCR).We con-ducted a sequence analysis of the entire HBV region in a case of non-B non-C chronic hepatitis in a 46-yearold female.A diagnosis of non-B non-C chronic hepatitis was made.Although HBV markers,such as HBs antibody(anti-HBs),anti-HBc,HBeAg and anti-HBe,were negative,HBV-DNA was positive.Nested PCR was performed to amplify the precore region of HBV-DNA and all remaining regions by long nested PCR.Sequence analysis of the two obtained bands was conducted by direct sequencing.Compared with the control strains,the ATG(Methionine)start codon in the X region had mut ated to GTG(Valine).It is assumed that a mutation at the start codon in the X region may be the reason why HBV markers are negative in some cases of hepatitis that involve occult HBV infection.

地西他滨联合维生素C治疗骨髓增生异常综合征的疗效及机制

目的:评估地西他滨联合维生素C治疗骨髓增生异常综合征(MDS)的疗效及机制。方法:选取2020年9月至2022年9月在我院初诊MDS患者78例为研究对象,根据患者选择的不同化疗方式分为两组,观察组(38例)应用地西他滨联合维生素C方案治疗,对照组(40例)单独应用地西他滨治疗,评估两组疗效。所有患者进行MDS相关突变基因检测,分析突变基因特点及与疗效的关系。结果:观察组治疗总反应率高于对照组(76.32%vs55.00%,P<0.05)。MDS患者基因突变检出率为71.79%,TET2突变患者治疗有效率高于对照组(100.00%vs 55.56%,P<0.05)。结论:MDS患者易发生基因突变,地西他滨联合维生素C较单独应用地西他滨治疗MDS临床疗效更显著,且反应应答率高,其机制可能与维生素C激活肿瘤细胞TET2的表达,增强去甲基化作用有关。