Novel 6-bp Deletion Mutation in visfatin Gene and Its Associations with Birth Weight and Bodyweight in Chinese Cattle

Visfatin, like insulin, induces phosphorylation of signal transduction proteins that operatate downstream of the insulin receptor. The present study is focused on detecting deletion of visfatin gene and analyzing its effect on growth traits in six Chinese cattle breeds （Nangyang, Luxi, Qinchuan, Jiaxian Red, Grassland Red, and Chinese Holstein） using DNA sequencing, PCR-SSCP and PCR-RFLP methods. For the first time, a 6-bp deletion of visfatin was described and two alleles were revealed：W and D. The χ2-test analysis demonstrated that all breeds were in agreement with Hardy-Weinberg equilibrium （P〉0.05）. The associations of the novel 6-bp deletion of visfatin gene with growth traits of Nanyang cattle at 6-, 12-, 18-, and 24-mon-old were analyzed. Birth weight, 12- and 24-mon-old cattle with genotype WW had greater birth weight and average daily gain than genotype WD （P〈0.01 or P〈0.05）. These results suggest that the deletion may influence the birth weight and bodyweight in 12 mon-old cattle.

DELETIONS AND POINT MUTATIONS OF p16,p15 GENE IN PRIMARY TUMORS AND TUMOR CELL LINES

Aberrations of chromosome 9 p21 22 are involved in the genesis of many forms of cancer.The gene p16 and p15 have been assigned to this region.Both p16 and p15 are an inhibitor of cyclin D cdk4,cyclin D cdk6 complex and have been implicated in a wide variety of cancer types,including the germline of patients with familial melanoma.In order to investigate and compare the status of p16,p15 gene in primary tumors and cell lines,we examined 357 primary tumors and 29 cell lines derived from diverse tumor types.In addition to analysis of these primary tumors and cell lines,blood specimens from 91 patients either with sporadic multiple cancers or from cancer prone families were also analyzed.The data showed the following:1)Homozygous deletions of p16,p15 were comparatively rare and far less common than previously reported,although hemizygous deletions were observed in a significant fraction of many tumor types;2)the incidence of p16,p15 deletions(either homozygous deletions or heterozygous deletions)varied significantly among different tumor types;3)most deletions involved in both p16 and p15 genes;4)sequence variations in the coding sequence of p16,p15 were comparatively rare among these tumor types,though mutations and polymorphisms were identified;5)some tumors which showed LOH at 9p,containing p16 and p15 gene,did not show deletions or point mutations in the p16,p15 gene.6)In a subset of retinoblastoma and osteosarcoma where no Rb gene mutations were present a significant fraction was found to contain p16,p15 gene deletions.

Correlation between the Insertion/Deletion Mutations of Prion Protein Gene and BSE Susceptibility and Milk Performance in Dairy Cows

Objective To investigate the 23 bp and 12 bp insertion/deletion(indel)mutations within the bovine prion protein(PRNP)gene in Chinese dairy cows,and to detect the associations of two indel mutations with BSE susceptibility and milk performance.Methods Based on bovine PRNP gene sequence,two pairs of primers for testing the 23 bp and 12 bp indel mutations were designed.The PCR amplification and agarose electrophoresis were carried out to distinguish the different genotypes within the mutations.Moreover,based on previous data from other cattle breeds and present genotypic and allelic frequencies of two indels mutations in this study,the corrections between the two indel mutations and BSE susceptibility were tested,as well as the relationships between the mutations and milk performance traits were analyzed in this study based on the statistical analyses.Results In the analyzed Chinese Holstein population,the frequencies of two"del"alleles in 23 bp and 12 bp indel muations were more frequent.The frequency of haplotype of 23del-12del was higher than those of 23del-12ins and 23ins-12del.From the estimated r2and D’values,two indel polymorphisms were linked strongly in the Holstein population(D’=57.5%,r2=0.257).Compared with the BSE-affected cattle populations from the reported data,the significant differences of genotypic and allelic frequencies were found among present Holstein and some BSE-affected populations(P<0.05 or P<0.01).Similarly,there were significant frequency distribution differences of genotypes and alleles among Chinese Holstein and several previous reported healthy dairy cattle(P<0.05 or P<0.01).Moreover,association of genotype and combined genotypes of two indel polymorphisms with milk performance and resistant mastitis traits were analyzed in Holstein population,but no significant differences were found(P>0.05).Conclusions These observations revealed that the influence of two indel mutations within the bovine PRNP gene on BSE depended on the breed and they did not affect the milk production traits,which layed the foundation for future selection of resistant animals,and for improving health conditions for dairy breeding against BSE in China.

Detection of Homozygous Deletions and Mutations in the CDKN2A Gene in Hydatidiform Moles

OBJECTIVE To investigate homozygous deletions and mutations in the CDKN2A gene(p16 INK4a and p14 ARF gene)in hydatidiform moles. METHODS A total of 38 hydatidiform mole samples and 30 villi samples were examined for homozygous deletions in the CDKN2A gene by PCR and for mutations by DHPLC. RESULTS i)Among 38 hydatidiform mole samples, homozygous deletions in the p16 INK4a exon 1 were identified in 5 cases(13.2%),while no homozygous deletions were found in the p16I NK4aexon 1 of 30 early-pregnancy samples.The rates of those deletions in hydatidiform compared to early-pregnancy villi samples was statistically significant(P=0.036).ii)No homozygous deletions in the p14 ARF exon 1 or p16 INK4a exon 2 were found in any of the hydatidiform moles or early-preganancy samples.iii) In all hydatidiform moles and early-pregnancy villi samples,no mutations were detected by DHPLC. CONCLUSION We suggest there may be a close correlation between homozygous deletions in the CDKN2A gene and occurrence of hydatidiform moles variation in the CDKN2A gene is mainly caused by homozygous deletions,while mutations may be not a major cause.

Therapy-related acute promyelocytic leukemia with FMS-like tyrosine kinase 3-internal tandem duplication mutation in solitary bone plasmacytoma: A case report

BACKGROUND Therapy-related acute promyelocytic leukemia(t-APL)is a rare complication observed in solitary bone plasmacytoma(SBP),and SBP after radiotherapy evolving to APL harboring the FMS-like tyrosine kinase 3-internal tandem duplication(FLT3-ITD)mutation has never been reported.Here,we present the first case reported until now.CASE SUMMARY We describe a 64-year-old woman who presented with lumbar pain and was initially diagnosed with SBP.However,after one year of radiotherapy treatment,this patient experienced a long-standing bone-marrow-suppressive period and finally developed APL harboring the FLT3-ITD mutation,as confirmed by analyses of clinical features,bone marrow morphology,flow cytometry,cytogenetic examination,and molecular biology.On admission,the patient had disseminated intravascular coagulation and intracranial hemorrhage,and the peripheral blood and bone marrow smear displayed abundant abnormal promyelocytes.Unfortunately,she died when the definite diagnosis was made.CONCLUSION The patient with t-APL harboring FLT3-ITD mutation evolving from SBP after radiotherapy had not been reported and had poor clinical outcomes.FLT3-ITD mutation in t-APL may be a potential pathogenesis of leukemogenesis.We should consider the potential risk of secondary neoplasms in SBP patients after radiotherapy.

Novel in-frame deletion mutation c.177_179del TAC of neurofibromatosis type 1 in a Chinese 4-year-old boy with binocular blindness

Dear editor,I am Dr.Jie Peng,from the Department of Ophthalmology,Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine,Shanghai,China.I write to present a case report of a novel in-frame deletion mutation c.17779del TAC of neurofibromatosis type 1 in a Chinese boy with bilateral blindness.Neurofibromatosis type 1(NF1;OMIM#162200),an autosomal dominant disease,is caused by mutations in the NF1gene.The incidence of this disease is around 1 in 3500

Clinical outcomes of EGFR-TKI treatment and genetic heterogeneity in lung adenocarcinoma patients with EGFR mutations on exons 19 and 21

Background:Epidermal growth factor receptor(EGFR) mutations,including a known exon 19 deletion(19 del) and exon 21 L858 R point mutation(L858R mutation),are strong predictors of the response to EGFR tyrosine kinase inhibitor(EGFR-TKI) treatment in lung adenocarcinoma.However,whether patients carrying EGFR 19 del and L858 R mutations exhibit different responsiveness to EGFR-TKls and what are the potential mechanism for this difference remain controversial.This study aimed to investigate the clinical outcomes of EGFR-TKI treatment in patients with EGFR 19 del and L858 R mutations and explore the genetic heterogeneity of tumors with the two mutation subtypes.Methods:Of 1127 patients with advanced lung adenocarcinoma harboring EGFR 19 del or L858 R mutations,532 received EGFR-TKI treatment and were included in this study.EGFR 19 del and L858 R mutations were detected by using denaturing high-performance liquid chromatography(DHPLC).T790 M mutation,which is a common resistant mutation on exon 20 of EGFR,was detected by amplification refractory mutation system(ARMS).Next-generation sequencing(NGS) was used to explore the genetic heterogeneity of tumors with EGFR 19 del and L858 R mutations.Results:Of the 532 patients,319(60.0%) had EGFR 19 del,and 213(40.0%) had L858 R mutations.The patients with EGFR 19 del presented a significantly higher overall response rate(ORR) for EGFR-TKI treatment(55.2%vs.43.7%,P = 0.017) and had a longer progression-free survival(PFS) after first-line EGFR-TKI treatment(14.4 vs.11.4 months,P = 0.034) compared with those with L858 R mutations.However,no statistically significant difference in overall survival(OS) was observed between the two groups of patients.T790 M mutation status was analyzed in 88 patients before EGFR-TKI treatment and 134 after EGFR-TKI treatment,and there was no significant difference in the co-existence of T790 M mutation with EGFR 19 del and L858 R mutations before EGFR-TKI treatment(5.6%vs.8.8%,P = 0.554)or after treatment(24.4%vs.35.4%,P = 0.176).In addition,24 patients with EGFR 19 del and 19 with L858 R mutations were analyzed by NGS,and no significant difference in the presence of multiple somatic mutations was observed between the two genotypes.Conclusions:Patients with EGFR 19 del exhibit longer PFS and higher ORR compared with those with L858 R mutations.Whether the heterogeneity of tumors with EGFR 19 del and L858 R mutations contribute to a therapeutic response difference needs further investigation.

APC gene mutations in Chinese familial adenomatous polyposis patients

AIM:To study the characteristics of APC(adenomatous polyposis coli)gene germline mutation in Chinese patients with familial adenomatous polyposis(FAP).METHODS:APC gene from 14 FAP families was amplified by polymerase chain reaction(PCR)and underwent direct sequencing to determine the micromutation type.For the samples without micromutation,the large fragment deletion of APC gene was examined by multiplex ligation-dependent probe amplification(MLPA).RESULTS:There were gene micromutations in 9 families with a micromutation detection rate of 64.3%(9/14),including 6 frameshift mutations(66.7%),1 nonsense mutation(11.1%)and 2 splicing mutations(22.2%).Large fragment deletions were detected by MLPA in 2 families.The total mutation detection rate of micromutations and large fragment deletions was 78.6%(11/14).CONCLUSION:The detection rate of APC gene germline mutation can be improved by direct sequencing combined with MLPA large fragment deletion detection.

COOH-terminal deletion of HBx gene is a frequent event in HBV-associated hepatocellular carcinoma

AIM:To investigate the hepatitis B virus (HBV) x gene (HBx) state in the tissues of HBV-related hepatocellular carcinoma (HCC) in Chinese patients and whether there were particular HBx mutations. METHODS: HBx gene was amplified and direct sequencing was used in genomic DNA samples from 20 HCC and corresponding non-cancerous liver tissues from HBsAg-positive patients. HBV DNA integration and HBx deleted mutation were validated in 45 HCC patients at different stages by Southern blot analysis and polymerase chain reaction methods. RESULTS: The frequencies of HBx point mutations were significantly lower in HCC than their corresponding non- cancerous liver tissues (11/19 vs 18/19, P = 0.019). In contrast, deletions in HBx gene were significantly higher in HCC than their non-cancerous liver tissues (16/19 vs 4/19, P < 0.001). The deletion of HBx COOH-terminal was detected in 14 HCC tissues. A specific integration of HBx at 17p13 locus was also found in 8 of 16 HCC, and all of them also exhibited full-length HBx deletions. Integrated or integrated coexistence with replicated pattern was obtained in 45.5% (20/45) - 56.8% (25/45) tumors and 40.9% (18/45) - 52.3% (23/45) non-tumor tissues. CONCLUSION: HBx deletion, especially the COOH- terminal deletion of HBx is a frequent event in HBV-associated HCC tissues in China. HBV integration had also taken place in partial HCC tissues. This supporting the hypothesis that deletion and probably integrated forms of the HBx gene may be implicated in liver carcinogenesis.

Abnormal Change of p53 Gene in Gastric and PrecancerousLesions and APC Gene Deletion in Gastric Carcinoma and Near Tissues

p53 gene mutation (exon4, 5, 6, 7, 8 and intron6) in gastric cancer and precancerous lesions and p53 gene (exon4 and ontron6), APC gene deletion in gastric carcinomas were studied by PCR/SSCP and PCR/RFLP- Results showed mutation rate of p53 in metaplasia, dysplasia and gastric carcinoma was 37. 5 % (3/8), 42. 11 % (8/19), 53. 33 (16/30) respectively- There was significant dif-ference among groups of metaplasia, dysplasia, cancer and normal controls. Noexon8 mutation was found in metaplasia and dysplasia, but 4 cases were found to have exon8 mutation in cancer group. It is suggested that exon8 mutation occurs at the late stage of gastric cancer, but exon 5, 6, 7 mutation occur in the course ofprecancerous lesion to cancer. Loss of heterozygosity (LOH) of exon4, intron6,APC was 47,37 % (9/19), 8. 73% (2/23), 16. 67 % (3/18) respectively. LOH of exon4 had something to do with poor differentiation, lymph node metastasis,depth of invasion- LOH of exon4 may be one of prognostic marker of gastric cancer. We are led to conclude that p53 gene mutation is an early event and perhaps work together with ras oncogene in gastric carcinogenesis

Mutations in the p16 gene in DMBA-induced pancreatic intraepithelial neoplasia and pancreatic cancer in rats

BACKGROUND：7,12-dimethylbenzanthracene（DMBA）-induced pancreatic intraepithelial neoplasia（PanIN）and pancreatic cancer in rats provide a classic model for uncovering the molecular mechanisms underlying pancreatic cancer.However,this model has not been characterized genetically,and in particular,the major genetic alterations in the p16 gene are unknown.METHODS： Lesions of PanlN and pancreatic cancer were induced with DMBA implantation in 40 rats, and control pancreatic tissue was obtained from 10 age-matched rats without exposure to DMBA. Pancreatic tissue was harvested three months after DMBA implantation and DNA was extracted. Homozy- gous deletions and point mutations of the pl6 （exons 1 and 2） gene were detected by PCR amplification and direct sequencing. RESULTS： DMBA implantation in the 40 rats induced 26 Pan- INs and 9 carcinomas. The overall frequency of p 16 alterations in the pancreatic tissue of these rats was 42.86% （15/35）, and the changes were point mutations, not homozygous deletions. p16 mutations were present in 30.77% （8/26） of the rats with PanIN and 77.78% （7/9） of the rats with carcinoma （P〈0.05）. The increasing incidence of p16 alterations was detected in 20.00% （1/5） of PanIN-1, 28.57% （2/7） of PanIN-2 and 35.71% （5/14） of PanIN-3 lesions. CONCLUSION： Our findings indicated that p16 alteration is a common event in the carcinogenesis of this model and that the mutation pattern is analogous to that of human lesions.

Exon Deletions of Parkin Gene in Patients with Parkinson Disease

Summary: Mutations in the parkin gene have recently been identified in familial and isolated patients with early-onset Parkinson disease (PD) and that subregions between exon 2 and 4 of the parkin gene are hot spots of deletive mutations. To study the distribution of deletions in the parkin gene among variant subset patients with PD in China, and to explore the role of parkin gene in the pathogenesis of PD, 63 patients were divided into early onset and later onset groups. Exons 1-12 were amplified by PCR, templated by the genomic DNA of patients, and then the deletion distribution detected by agarose electrophoresis. Four patients were found to be carrier of exon deletions in 63 patients with PD. The location of the deletion was on exon 2 (1 case), exon 3 (2 cases) and exon 4 (1 case). All patients were belong to the group of early onset PD. The results showed that parkin gene deletion on exon 2, exon 3 and exon 4 found in Chinese population contributes partly to early onset PD.

EXPRESSION AND DELETION ANALYSIS OF EcoRII ENDONUCLEASE AND METHYLASE GENE

Objective. To clone complete EcoRII restriction endonuclease gene (ecoRIIR) and methyltransferase gene (ecoRIIM) in one vector and to analyze the coordinating expression of this whole R M system.Methods. Unidirectional deletion subclones were constructed with ExoIII.ecoRIIR/M genes were preliminarily located in the cloned fragment according to the enzyme activities of subclones. Exact deletion sites were determined by sequencing, and transcriptional start sites were determined by S1 mapping. Results. The DNA fragment which was cloned into pBluescript SK+contained intact ecoRIIR gene andecoRIIM gene, and two transcriptional start sites of ecoRIIR gene were determined. 132bp to 458bp from 3’end of ecoRIIR gene are indispensable to enzyme activities and deletion of 202bp from 3’end of ecoRIIM gene made enzyme lose the capability in DNA protection to resist specific cut with EcoRII endonuclease (EcoRII.R). Deletion of the coding and flanking sequences of one gene did not affect the expression of the other gene, and the recombinants only containing ecoRIIR gene appeared to be lethal to dcm+host. Conclusion. ecoRIIM gene linking closely to ecoRIIR gene is very important for the existence of the R M system in process of evolution, but the key tocontrol EcoRII R M order may not exist in transcriptional level .

Detection of mitochondrial DNA deletion by a modified PCR method

Objective: To develop a simple and efficient method for detecting small populations of mitochondrial DNA deletion. Methods: Peripheral blood cell DNA was obtained from a victim who was accidently exposed to a 60Co radiation source 11 years ago. Using the DNA as template, PCR was performed to generate multiple products including true deletions and artifacts. The full length product was recovered and used as template of secondary PCR. The suspicious deletion product of mtDNA could be confirmed if it was only yielded by first PCR. Using either original primers or their nested primers, the suspicious deletion product was amplified and authenticated as true deletion product. The template was recovered and determined to be a deletion by sequencing directly. Results: A new mtDNA deletion, spanning 889 bp from nt11688 to nt12576, was detected in the peripheral blood cells of the victim. Conclusion: The new PCR-based method is more efficient in detecting small populations of mtDNA deletion than other routine methods. MtDNA deletion is found in the victim, suggesting there is relationship between the deletion and phenotypes of the disease.

Codon 201 Mutation of DCC Gene and Tumor Biologic Behavior in Human Colorectal Carcinoma

Objective To explore the relationship between a point mutation of codon 201 in deleted in colorectal carcinoma (DCC) gene and the biological behavior of colorectal carcinoma. Methods Tumor tissues and matched adjacent normal colon mucosa collected in 35 patients during surgical resection for colorectal carcinoma were analyzed. Forty normal colon mucosa tissues obtained by biopsy from patients who had neither colorectal tumor nor a family history of colorectal cancer during colonscopic examination were used as control. Codon 201 mutation was detected with allele specific PCR and a restriction enzyme digestion method. The tumors were reviewed as clinical data, tumor location, histology, metastasis, and pathological staging (Dukes classification). Results The frequency of mutation at codon 201 in tumor tissue and corresponding adjacent normal mucosa was 71.4% and 60%, respectively, and either of the rates was significantly higher than that of normal control(32.5%). The point mutation rate in tumor tissues did not differ from that in the corresponding normal adjacent tissues. Statistic analysis showed that the mutation rate had no relationship to the sex, age of the patients, the histological pattern, differentiation, and invasion depth of the tumors. However, 93.8% of the mutation rate in colorectal cancer with lymph node invasion and/or distant metastasis is significantly higher than 52.6% of mutant rate in colorectal cancer without lymph nodes invasion or metastasis (P<0 05). Conclusion The point mutation at codon 201 of DCC gene is an early genetic event in colorectal cancer, and play some role in invasion and metastasis of colorectal carcinoma. It may serve as a useful genetic marker for identifying higher risk patients with colorectal carcinoma.

Mutation of imprinted gene BWRIA in nephroblastoma

Objective To investigate the mutation of the BWR1A gene, an imprinted gene, in nephroblastoma and explore the relationship between mutation of BWR1A and the pathogenesis of embryonic tumors. Methods Fifty-five cases of nephroblastoma for mutation of the BWR1A gene were screened by PCR-SSCP and DNA sequencing. Results Of the 55 cases, 6 showed abnormal SSCP-band shifts. DNA sequencing showed 1 case of G deletion at 1093 locus, resulting in a stop codon TGA. Conclusion The mutation of BWR1A gene may be involved in ontogenesis of embryoma.5 refs,1 fig,2 tabs.

Expression,deleton and mnutation of ρ16 gene in human gastric cancer

AIM To investigate the relationship between the expression of p16 gene and the gastric carcinogenesis,depth of invasion and lymph node metastases, and to evaluate the deletion and mutation of exon 2 in p16 gene in gastric carcinoma.METHODS The expression of P16 protein was examined by streptavidin-peroxidase conjugated method (S-P); the deletion and mutation of p16 gene were respectively examined by polymerase chain reaction (PCR) and polymerase chain reaction single-strand conformation polymorphism analysis (PCR-SSCP) in gastric carcinoma.RESULTS Expression of P16 protein was detected in 96.25% (77/80) of the normal gastric mucosa, in 92.00% (45/50) of the dysplastic gastric mucosa and in 47.54% (58/122) of the gastric carcinoma. The positive rate of P16 protein expression in gastric carcinoma was significantly lower than that in normal gastric mucosa and dysplastic gastric mucosa (P＜0.05). The positive rate of P16 protein expression in mucoid carcinoma 10.00% (1/ 10) was significantly lower than that in poorly differentiated carcinoma 51.22% ( 21/ 41 ),undifferentiated carcinoma 57.69% (15/26) and signet ring cell carcinoma 62.50% (10/ 16) (P＜0.05). The positive rate of p16 protein in 30 cases paired primary and lymph node metastatic gastric carcinoma: There was 46.67% (14/30) in primary gastric carcinoma, 16.67% (5/30) in lymph node metastatic gastric carcinoma. The positive rate of lymph node metastatic carcinoma was significantly lower than that of primary carcinoma (P＜0.05). There was of p16 gene mutation in exon 2, but 5 cases displayed deletion of p16 gene in exon 2 in the 25 primary gastric carcinomas.CONCLUSIONS The expression loss of P16 protein related to the gastric carcinogenesis, gastric carcinoma histopathological subtypes and lymph metastasis. The mutation of p16 gene in exon 2 may not be involved in gastric carcinogenesis. But the deletion of p16 gene in exon 2 may be involved in gastric carcinogenesis.

A novel deletion mutation, c.1296delT in the BCOR gene, is associated with oculo-facio-cardio-dental syndrome

The purpose of the present study was to analyze the clinical phenotypes of a girl with oculo-facio-cardio-dental(OFCD)syndrome and to identify the potential pathogenic mutation responsible for her disease. The patient underwent detailed clinical examinations and phenotype data were collected over a follow-up period of 9 years. Mutation analysis of the candidate gene BCOR was performed with polymerase chain reaction and Sanger sequencing. BCOR of 60 unrelated normal individuals were also sequenced as a control group. Clinical phenotyping and follow-up study results indicate that this patient had multiple system anomalies including ocular, facial, cardiac, dental, and limb malformations. In addition, papilloma of the choroid plexus was identified, which represents the first report of this phenotype in an OFCD patient. A novel deletion mutation, c.1296 delT in exon4 of the BCOR gene, was identified in this patient and was not found in her parents or in 60 normal unrelated individuals. This deletion was a frameshift mutation and is proposed to encode a premature stop codon, thus producing a truncated protein. Our patient fitted the diagnostic criteria for OFCD syndrome and we report the first papilloma of the choroid plexus in an OFCD patient, expanding the recognized phenotypic spectrum of this disease. Meanwhile, we identified a novel deletion mutation that may cause OFCD syndrome.

Clinical Performance of Cell-Free Fetal DNA Testing for Fetal Aneuploidies and Subchromosomal Deletions/Duplications in a Cohort of 19,531 Pregnancies

Objective:We aim to assess the clinical performance of cell-free fetal DNA(cffDNA)testing for detecting common fetal aneuploidies as well as subchromosomal deletions/duplications and explore the pregnancy decisions in screen-positive cases.Methods:A cohort of 19,531 pregnant women was offered cffDNA testing for detection of trisomies 21,18,and 13(T21,T18,and T13);sex chromosome aneuploidies(SCAs);and subchromosomal deletions/duplications.Screen-positive cases were confirmed by karyotyping and single-nucleotide polymorphism array analysis.Results:A total of 47 cases failed the test.The overall screen-positive rate of chromosomal abnormalities was 1.07%(208/19,484),including 57 cases with T21,18 cases with T18,7 cases with T13,106 cases with SCAs,and 20 cases of subchromosomal deletions/duplications.Positive predictive values were 91.30%(42/46),38.46%(5/13),33.33%(2/6),41.33%(31/75),and 27.78%(5/18),respectively.There was no significant difference in the screening of fetal chromosomal aneuploidies in the high-risk group compared with the low-risk group(P>0.05).All of the pregnant women who had confirmed fetal T21,T18,or T13 terminated their pregnancies,except for a case of T13 mosaic,whereas 45.16%(14/31)of women with fetal SCAs continued their pregnancies.Furthermore,17 pregnant women with positive screens for T21,T18,or T13 without a subsequent diagnosis chose to terminate their pregnancy,whereas 29 of 31 women with SCAs chose to continue their pregnancies.Conclusions:CffDNA testing exhibited good screening accuracy for T21,T18,and T13 and also contributed to detecting fetal SCAs and subchromosomal deletions/duplications.Pregnant women with fetal 47,XXX or 47,XYY were more willing to terminate their pregnancy than those with fetal 45,X or 47,XXY.

A novel deletion-frameshift mutation in the S1 region of HERG gene in a Chinese family with long QT syndrome

Background The congenital Long QT syndrome （LQTS） is a hereditary cardiac channelopathy that is characterized by a prolonged QT interval,syncope,ventricular arrhythmias,and sudden death.The chromosome 7-linked type 2 congenital LQTS （LQT2） is caused by gene mutations in the human ether-a-go-go-related gene （HERG）.Methods A Chinese family diagnosed with LQTS were screened for KCNQ1,HERG and SCN5A,using polymerase chain reaction （PCR）,direct sequencing,and clong sequencing.We also investigated the mRNA expression of the HERG gene.Results We identified a novel i414fs＋98X mutation in the HERG gene.The deletion mutation of 14-bp in the first transmembrane segment （S1） introduced premature termination codons （PTCs） at the end of exon 6.This mutation would result in a serious phenotype if the truncated proteins co-assembled with normal subunit to form the defective channels.But only the proband was symptomatic.Conclusions We found that the mRNA level of the HERG gene was significantly lower in 1414fs＋98X carriers than in noncarriers.We found a novel 1414fs＋98X mutation.The mRNA level supports that NMD mechanism might regulate the novel mutation.