RDH12-associated retinal degeneration caused by a homozygous pathogenic variant of 146C>T and literature review.

AIM: To describe the clinical, electrophysiological, and genetic features of an unusual case with an RDH12 homozygous pathogenic variant and reviewed the characteristics of the patients reported with the same variant. METHODS: The patient underwent a complete ophthalmologic examination including best-corrected visual acuity, anterior segment and dilated fundus, visual field, spectral-domain optical coherence tomography (OCT) and electroretinogram (ERG). The retinal disease panel genes were sequenced through chip capture high-throughput sequencing and Sanger sequencing was used to confirm the result. Then we reviewed the characteristics of the patients reported with the same variant. RESULTS: A 30-year male presented with severe early retinal degeneration who complained night blindness, decreased visual acuity, vitreous floaters and amaurosis fugax. The best corrected vision was 0.04 OD and 0.12 OS, respectively. The fundus photo and OCT showed bilateral macular atrophy but larger areas of macular atrophy in the left eye. Autofluorescence shows bilateral symmetrical hypo-autofluorescence. ERG revealed that the amplitudes of a- and b-wave were severely decreased. Multifocal ERG showed decreased amplitudes in the local macular area. A homozygous missense variant c.146C>T (chr14:68191267) was found. The clinical characteristics of a total of 13 patients reported with the same pathologic variant varied. CONCLUSION: An unusual patient with a homozygous pathogenic variant in the c.146C>T of RDH12 which causes late-onset and asymmetric retinal degeneration are reported. The clinical manifestations of the patient with multimodal retinal imaging and functional examinations have enriched our understanding of this disease.

Ruxolitinib induces apoptosis and pyroptosis of anaplastic thyroid cancer via the transcriptional inhibition of DRP1-mediated mitochondrial fission.

Anaplastic thyroid carcinoma (ATC) has a 100% disease-specific mortality rate. The JAK1/2-STAT3 pathway presents a promising target for treating hematologic and solid tumors. However, it is unknown whether the JAK1/2-STAT3 pathway is activated in ATC, and the anti-cancer effects and the mechanism of action of its inhibitor, ruxolitinib (Ruxo, a clinical JAK1/2 inhibitor), remain elusive. Our data indicated that the JAK1/2-STAT3 signaling pathway is significantly upregulated in ATC tumor tissues than in normal thyroid and papillary thyroid cancer tissues. Apoptosis and GSDME-pyroptosis were observed in ATC cells following the in vitro and in vivo administration of Ruxo. Mechanistically, Ruxo suppresses the phosphorylation of STAT3, resulting in the repression of DRP1 transactivation and causing mitochondrial fission deficiency. This deficiency is essential for activating caspase 9/3-dependent apoptosis and GSDME-mediated pyroptosis within ATC cells. In conclusion, our findings indicate DRP1 is directly regulated and transactivated by STAT3; this exhibits a novel and crucial aspect of JAK1/2-STAT3 on the regulation of mitochondrial dynamics. In ATC, the transcriptional inhibition of DRP1 by Ruxo hampered mitochondrial division and triggered apoptosis and GSDME-pyroptosis through caspase 9/3-dependent mechanisms. These results provide compelling evidence for the potential therapeutic effectiveness of Ruxo in treating ATC.

Trends and projections of inflammatory bowel disease at the global, regional and national levels, 1990-2050: a bayesian age-period-cohort modeling study.

BACKGROUND: Inflammatory bowel disease (IBD) is a global health concern with varying levels and trends across countries and regions. Understanding these differences is crucial for effective prevention and treatment strategies. METHODS: Using data from the 2019 Global Burden of Disease study, we examine IBD incidence, mortality, and disability-adjusted life years (DALYs) rates in 198 countries from 1990 to 2019. To assess changes in the burden of IBD, estimated annual percentage changes (EAPC) were calculated, and a Bayesian age-period-cohort model was used to predict the future 30-year trends of IBD. RESULTS: In 2019, there were 405,000 new IBD cases globally (95% uncertainty interval (UI) 361,000 to 457,000), with 41,000 deaths (95% UI 35,000 to 45,000) and 1.62million DALYs (95% UI 1.36-1.92million). The global age-standardized incidence rate in 2019 was 4.97 per 100,000 person-years (95% UI 4.43 to 5.59), with a mortality rate of 0.54 (95% UI 0.46 to 0.59) and DALYs rate of 20.15 (95% UI 16.86 to 23.71). From 1990 to 2019, EAPC values for incidence, mortality, and DALYs rates were - 0.60 (95% UI - 0.73 to - 0.48), - 0.69 (95% UI - 0.81 to - 0.57), and - 1.04 (95% UI - 1.06 to - 1.01), respectively. Overall, the burden of IBD has shown a slow decline in recent years. In SDI stratification, regions with higher initial SDI (high-income North America and Central Europe) witnessed decreasing incidence and mortality rates with increasing SDI, while regions with lower initial SDI (South Asia, Oceania, and Latin America) experienced a rapid rise in incidence but a decrease in mortality with increasing SDI. Predictions using a Bayesian model showed lower new cases and deaths from 2020 to 2050 than reference values, while the slope of the predicted incidence-time curve closely paralleled that of the 2019 data. CONCLUSION: Increasing cases, deaths, and DALYs highlight the sustained burden of IBD on public health. Developed countries have stabilized or declining incidence rates but face high prevalence and societal burden. Emerging and developing countries experience rising incidence. Understanding these changes aids policymakers in effectively addressing IBD challenges in different regions and economic contexts.

[Hematologic Phenotype and Genotype Analysis of Patients with Hemoglobin Variants].

OBJECTIVE: To study the hematologic and molecular features of 14 patients with hemoglobin (Hb) variants, so as to provide reference data for its laboratory screening. METHODS: A total of 1 029 samples were screened by high performance liquid chromatography (HPLC) on the Bio-Rad VariantⅡHPLC system. GAP-PCR and reverse dot blot (RDB) were used to detect common mutation of α and ß globin gene in Chinese. DNA sequencing for α and ß globin gene was simultaneously performed in samples with abnormal spectrum peak and negative thalassemia gene. RESULTS: In 1 029 samples, 10 types of structural Hb variants were detected in14 cases (1.36%), including 1 case of Hb E / ß- thalassemia, 1 case of Hb E /α- thalassemia (HbH disease), 2 cases of HbG-Taipei, 2 cases of Hb Q-Thailand, 2 cases of Hb Youngstown, 1 case of Hb Guangzhou-Hangzhou, 1 case of Hb M-Boston, 1 case of Hb G-Siriraj, 1 case of Hb J-Baltimore, 1 case of Hb J-Sicilia and 1 case of Hb Tamano. CONCLUSION: The occurrence of abnormal structural Hb variants with many genotypes in Shanghai is unique. Except for Hb E, Hb Youngstown, and Hb M-Boston, other types of heterozygous are normal in phenotypes, and symptoms such as hemolysis and anemia often occur when other diseases are combined.

Rosiglitazone alleviates lipopolysaccharide-induced inflammation in RAW264.7 cells via inhibition of NF-κB and in a PPARγ-dependent manner.

Rosiglitazone is a synthetic peroxisome proliferator-activated receptor (PPAR)γ agonist widely used for the treatment of type 2 diabetes. Recent studies have demonstrated that rosiglitazone displays anti-inflammatory effects. The present study aimed to investigate whether rosiglitazone alleviates decreases in RAW264.7 cell viability resulting from lipopolysaccharide (LPS)-induced inflammation, as well as exploring the underlying mechanism. A macrophage inflammatory injury model was established by treating RAW264.7 cells with 100 ng/ml LPS. Cells were divided into LPS and rosiglitazone groups with different concentrations. Cell viability was assessed by performing an MTT assay. The expression of inflammatory cytokines was detected by conducting enzyme-linked immunosorbent assays and reverse transcription-quantitative PCR. Nitric oxidesecretion was assessed using the Griess reagent system. The expression levels of key nuclear factor-κB pathway-associated proteins were detected via western blotting. Rosiglitazone alleviated LPS-induced decrease in RAW264.7 cell viability and inhibited inflammatory cytokine expression in a concentration-dependent manner. Rosiglitazone significantly inhibited LPS-induced upregulation of p65 phosphorylation levels and downregulated IκBα expression levels. However, rosiglitazone-mediated inhibitory effects were reversed by PPARγ knockdown. The results of the present study demonstrated that rosiglitazone significantly inhibited LPS-induced inflammatory responses in RAW264.7 macrophage cells, which was dependent on PPARγ activation and NF-κB suppression.

Gestational weight gain and risk of autism spectrum disorders in offspring: a systematic review and meta-analysis.

It has been revealed that gestational weight gain (GWG) influences the risk of autism spectrum disorder (ASD) in the offspring, but the findings are inconsistent. The current study aimed to evaluate the relationship between GWG and risk of ASD in offspring. Four electronic databases were searched up to August 28 2018 to identify observational studies reporting the association between GWG and risk of ASD in the offspring. Nine studies which met the inclusion criteria were included in the systematic review. Finally, five studies with a total of 3793 children with ASD were included in the meta-analysis. The-results indicated that excessive GWG might increase the risk of ASD in offspring (p = .0008, OR = 1.23, 95% confidence interval (CI) 1.09-1.38). More high quality cohort studies are needed to confirm this result. This research has the potential to inspire new research on ASD and promote efforts to design appropriate interventions against excessive GWG.Impact statementWhat is already known on this subject? It has been revealed that gestational weight gain (GWG) influences the risk of autism spectrum disorder (ASD) in the offspring, but the findings are inconsistent.What the results of this study add? This is the first systematic review and meta-analysis on the association between GWG and ASDs in offspring. This study suggested that excessive GWG was associated with higher risk of ASD in offspring.What the implications are of these findings for clinical practice and/or further research? More high quality cohort studies are needed to confirm this result. This research has the potential to inspire new research on ASD and promote efforts to design appropriate interventions against excessive GWG.

Therapeutic efficacy of nutritional support by percutaneous endoscopic gastrostomy in critically ill patients: A self-control clinical trial.

BACKGROUND & OBJECTIVE: Percutaneous endoscopic gastrostomy (PEG) is a procedure to provide enteral nutrition for critically ill patients. It is commonly used in clinical practice; however, the widespread use of PEG is controversial. Our objective was to evaluate the therapeutic effect of nutritional support by PEG in these critically ill patients. METHODS: A total of 64 critically ill patients including 41 males and 23 females (aged 23-84) were identified by the Acute Physiology and Chronic Health Evaluation (APACHE) II scoring system during September 2004 to June 2012. The nutritional status before and after PEG was mainly assessed by the tricep skinfold thickness and serum albumin level. The nutritional status and pathological condition were assessed at 4, 8 and 12 weeks before and after PEG feeding. The assessment was according to the classical method of the human nutritional status. Follow-up was performed at one month, three months and 1.5 year after gastrostomy. Statistical analysis was performed by SPSS 11.5 software. The incidence of inhalation pneumonia and gastroesophageal regurgitation was compared by chi square (χ2) test. P<0.05 were considered statistically significant. RESULTS: Among the 64 patients, 9 patients died of their former diseases or related symptoms. Postoperative follow-up showed that both nutritional status and complications were improved after PEG in 55 patients (P<0.05). The serum albumin and tricep skinfold thickness levels were significantly increased. The incidence of hypoglycemia, hypocalcemia, hypokalemia and hyponatremia were lower than pre-operation. The frequencies of complications were significantly reduced. No severe complications occurred in any patient. CONCLUSIONS: Our study confirmed that PEG was a good long-term route of nutritional supply with no serious complications for critically ill patients.

Prolonged small vessel vasculitis with colon mucosal inflammation as first manifestations of Behçet's disease.

Behçet's disease is a chronic, relapsing, systemic vasculitis of unknown aetiology. Patients present manifestations of gastrointestinal complications, including mouth lesions, small and large intestinal lesions, and vascular lesions in the abdomen. In some cases, the intestinal ulcers of patients with Behçet's disease are indistinguishable from those of Crohn's disease, tuberculosis, vasculitis and other diseases. In this article, we present a case of atypical Behçet's disease with a complicated medical history and multisystem damage, for the purpose of better management of this disease.

Exome sequencing revealed novel germline mutations in Chinese Peutz-Jeghers syndrome patients.

BACKGROUND AND AIMS: Peutz-Jeghers Syndrome (PJS) is an autosomal dominant disorder which predisposes to the development of various cancers. Germline mutation in the serine/threonine kinase 11 gene (STK11) is known as one of the major causes of PJS. However, a notable proportion of PJS samples do not carry any mutation in STK11, suggesting possible genetic heterogeneity in the disease and the existence of other causative variants. METHODS AND RESULTS: In order to identify other germline variants in the coding regions of the genome that are associated with PJS, we performed exome sequencing in three Chinese individuals with PJS and identified 16 common germline variants (12 protein-coding including STK11, 4 in pre-microRNAs). We further validated protein-coding variants in six PJS individuals (three with wild-type STK11) and predicted the functional impact. As result, we found that 7 coding variants are likely to have functional impacts. Especially, we identified 2 new germline variants which are represented in all six PJS samples and are independent of STK11 mutation. CONCLUSIONS: Our study provided an exomic view of PJS. The germline variants identified in our analysis may help to resolve the complex genetic background of the disease and thus lead to the discovery of novel causative variants of PJS.

Inhibitory effect of ARHI on pancreatic cancer cells and NF-κB activity.

The aim of this study was to investigate the effect of aplasia ras homolog member I (ARHI) on proliferation, apoptosis and the cell cycle in the pancreatic cancer cell line PANC-1. The study also aimed to examine the effect of ARHI on the activity of the nuclear factor (NF)-κB and to determine whether ARHI acts as a tumor suppressor in the development of pancreatic cancer by inhibiting the activity of NF-κB. A pIRES2­EGFP­ARHI vector, constructed by reverse transcrition (RT)­PCR, was transiently transfected into the PANC-1 cells and analyzed for the expression of the ARHI protein by western blotting. A MTT assay was used to quantify cell proliferation, and apoptosis was analyzed by flow cytometry. The NF­κB signaling pathway, specifically the pathway using the nuclear phosphorylated p65 isoform, was analyzed by western blotting. Expression of the ARHI protein was detected by western blotting subsequent to the PANC-1 cells being transiently transfected with the pIRES2­EGFP­ARHI construct. Cell proliferation was strongly inhibited in the PANC-1 cells transfected with pIRES2­EGFP­ARHI. The cell cycle assays indicated an increase in the number of cells at the G0/G1 phase and a decrease in the cells at the S phase, but the difference was not significant (P>0.05). Time course studies also indicated a marked increase in the apoptotic index following transient transfection, as well as a gradual decrease in the expression of the nuclear phosphorylated p65 protein. ARHI acts as a tumor suppressor by downregulating the NF­κB signaling pathway, which results in the inhibition of cell proliferation, apoptosis and the cell cycle in the pancreatic tumor PANC-1 cell line.

Aplasia ras homolog member I is downregulated in gastric cancer and silencing its expression promotes cell growth in vitro.

BACKGROUND AND AIM: Aplasia ras homolog member I (ARHI) is a maternally imprinted tumor suppressor gene. ARHI protein is widely expressed in many types of human tissues; however, its expression is frequently reduced or absent in various tumors and plays a tumor suppressor role for in vitro study. In this study, we investigated the expression level of ARHI in gastric cancer in order to investigate the function of ARHI and signaling pathways that might be linked during gastric cancer development. METHODS: ARHI mRNA and protein expression levels were analyzed in primary gastric cancer tissues, adjacent noncancerous gastric tissues and gastric cancer cell lines using semi-quantitative polymerase chain reaction, western blotting and immunohistochemistry, respectively. RESULTS: Our results showed that both mRNA and protein expression levels of the ARHI gene were significantly downregulated (P < 0.05) in gastric cancer tissues and cell lines compared to the corresponding normal control groups. The protein expression level of ARHI was not associated with age, gender, location of tumor, tumor size or metastasis in patients with gastric cancer. However, a significant correlation between the level of ARHI protein expression and the degree of tumor differentiation and Tumor-Node-Metastasis stage was observed (P < 0.05). Furthermore, results of the methyl thiazolyl tetrazolium and Transwell assays and flow cytometric analysis showed increased cell proliferation, migration and anti-apoptotic capacities in the well-differentiated gastric cancer MKN-28 cell line, which has stably silenced ARHI protein expression. CONCLUSION: Our data indicate that ARHI expression is downregulated in human gastric cancer and it may be a novel tumor suppressive target for gastric cancer therapy.

[A preliminary study on intravitreal injection of bevacizumab for treatment of neovascular age-related macular degeneration].

OBJECTIVE: To evaluate the short-term safety of intravitreous bevacizumab (Avastin) and its effects on visual acuity (VA) and subfoveal choroidal neovascularization (CNV) in patients with neovascular age-related macular degeneration (ARMD). METHODS: Single-center, uncontrolled clinical study. Five ARMD patients (5 eyes) with subfoveal CNV and best-corrected VA (BCVA) less than 0.1 were participated. Patients were treated with an intravitreous injection of bevacizumab (1.5 mg, 0.06 ml). Ophthalmologic evaluations included BCVA test, ocular examination, intraocular pressure (IOP) measurement, optical coherence tomography (OCT) imaging and fluorescein angiography (FFA). RESULTS: There were no ocular or systemic adverse events observed, except a mild elevation of IOP [26 mm Hg (1 mm Hg = 0.133 kPa)] in 1 case on the 3rd day after injection, which was controlled by topical medication. One out of 5 eyes had a significant improvement of BCVA (from 0.1 improved to 0.4) in one week after injection. By 2 months, the BCVA increased in 4 cases (increased 1 to 6 lines) and 3 of them remained stable for 4 to 6 months and 1 decreased at the 4 th month post injection. The thickness of central retina reduced 5.9% to 41.4% and FFA revealed a remarkable reduction or an absence of leakage from CNV in 3 eyes by the 4th month. CONCLUSION: Our preliminary results are promising, showing that intravitreous bevacizumab therapy is well tolerated with an improvement in VA, OCT, and FFA outcomes. A multi-center randomized controlled clinical trial is needed to evaluate the long-term safety and effectiveness of intravitreous bevacizumab therapy on neovascular ARMD.

[Studies on inherited coagulation factor VII deficiency and tissue factor abnormality in a pedigree].

OBJECTIVE: To investigate the mechanism of clinical haemorrhage in an inherited coagulation factor VII (FVII) deficiency and tissue factor abnormality pedigree. METHODS: All exons, exon-intron boundaries and the 3', 5' untranslated sequences of FVII and tissue factor (TF) genes were amplified by PCR and sequenced directly. Any mutation identified by direct sequencing was confirmed by reverse sequencing. FVII cDNA of the proband was synthesized with random primers and amplified by nest PCR. RESULTS: 55C-->T heterozygous mutation located in promoter of FVII gene was identified in the proband. The heterozygous mutation was derived from his mother. Tracing the other pedigree members found that his sister had the same heterozygous mutation and the others had wild-type FVII genes. A 9363 C-->T (Arg131Trp) heterozygous polymorphism in TF gene, which was 2.63% frequency of T allele polymorphism, was found in all of the pedigree members. CONCLUSION: It was the first report that the -55C-->T heterozygous mutation in FVII gene and the Arg131Trp heterozygous polymorphism in TF gene explained the clinical symptom of the proband.

Factor X Shanghai and disruption of translocation to the endoplasmic reticulum.

BACKGROUND AND OBJECTIVES: Most secreted proteins, including coagulation factor X (FX), are synthesized with a signal peptide, which is necessary for targeting the nascent polypeptide into the endoplasmic reticulum. Characterization of naturally occurring mutations may provide insights into the functional roles of the amino acids in the signal peptide. DESIGN AND METHODS: A 52-year old male patient with type I FX deficiency was studied. Mutations were searched for by FX gene (F10) sequencing. The wild-type and the mutant FX proteins were expressed in transfected cells and then immunological assays were performed. Pulse-chase experiments and cell-free expression studies were conducted to determine the cellular fate of the mutant FX molecules. RESULTS: The patient we studied was homozygous for a substitution of arginine for serine at codon -30 in the signal sequence of F10. Immunoassays detected low FX antigen levels in both the conditioned media and lysates of the cells expressing the mutant protein. Pulse-chase analysis showed that only trace amounts of the mutant FX protein were detectable in the conditioned media, and that the mutant molecules did not accumulate inside the cells either. The results of cell-free expression studies showed that although the transcription and translation of the mutant construct were normal, no post-translational processing, such as N-linked glycosylation, occurred in the presence of microsomes. INTERPRETATION AND CONCLUSIONS: These findings suggest that substitution of a neutral polar amino acid, serine by arginine, in the hydrophobic core of FX signal peptide severely impairs the ability of the protein to enter the endoplasmic reticulum and results in FX deficiency.

[Severe hereditary coagulation factor V deficiency caused by two novel heterozygous mutations].

OBJECTIVE: To identify gene mutations of a pedigree with inherited factor V (FV) deficiency. METHODS: The activated partial thromboplastin time (APTT), prothrombin time (PT), FV activity (FV:C) and FV antigen (FV:Ag) tests were performed for phenotypic diagnosis. The genomic DNA was extracted from the peripheral blood of the proband and all the 25 exons and their flanks of FV gene were amplified by polymerase chain reaction (PCR). The PCR products were screened by direct sequencing and the mutations were further confirmed by restriction enzyme digestion. RESULTS: APTT, PT, TT, FV:C, FV:Ag of the proband were 249.2 s, 46.6 s, 17.9 s, 0.1% and 1.5%, respectively. FII, FVII, FVIII, FIX, FX activities, vWF and Fg were within normal ranges. Taking the GenBank Z99572 sequence as the reference, four mutations were identified in FV gene of the proband. They were a heterozygous two bases deletion in exon 13 (2238 approximately 2239delAG) introducing a frameshift and a premature stop at codon 689, and a heterozygous missense mutation in exon 23 (G6410T) resulting in the substitution of Gly for Val at codon 2079, respectively. The proband's father and mother were heterozygous for G6410T and for 2238 approximately 2239delAG, respectively. CONCLUSION: The severe FV deficiency of the proband is caused by a frameshift mutation of 2238 approximately 2239delAG and a missense mutation of G6410T, which haven't been identified before.

[The inherited coagulation factor XI deficiency caused by intronic mutation IVS J-4delgttg].

OBJECTIVE: To identify gene defect in a Chinese pedigree of hereditary coagulation factor XI (FXI) deficiency. METHODS: The peripheral blood samples were collected from the proband and her family members. The plasma PT, APTT, FXI:C and FXI:Ag were assayed. The FXI gene exons and exon-intron boundaries of the proband were amplified by PCR and then sequenced directly. The mRNA of FXI in the peripheral blood was analyzed with RT-PCR. RESULTS: The proband and some of her family members had prolonged APTT. The plasma FXI:C and FXI:Ag of the proband, her brother and her parents were lower than 10% and 50% of the normal values, respectively. Nucleotide sequence analysis revealed that the proband and her brother had a homozygous mutation of IVS J-4delgttg in FXI gene. The mutation was inherited from her parents who were heterozygotes. The mutation was not found in 60 normal subjects. No FXI mRNA was detected in peripheral blood sample of the proband. CONCLUSION: The IVS J-4delgttg is a novel mutation causing FXI deficiency, which may interfere with mRNA splicing.

[Study on the molecular mechanism of antithrombin gene C2759T (Leu99Phe) mutation causing antithrombin deficiency].

OBJECTIVE: To study the molecular mechanism of antithrombin (AT) gene C2759T (Leu99Phe) mutation causing AT deficiency. METHODS: A mutated AT cDNA expression plasmid ATM2759 was constructed by mega-primer method. ATM2759 and wild type AT cDNA expression plasmid ATN were transfected into COS7 cells or CHO cells by using Superfect reagent respectively for in vitro expression study and immunofluorescence assay. RESULTS: The antigen levels of AT (AT:Ag) in the cell lysate of ATM2759 transfected COS7 cells and the cell culture supernatant were 174.97% and 35.63% of that of ATN transfected COS7 cells respectively, whereas the AT activity in the cell culture supernatant was 47.73% of the control's. Immunofluorescence analysis showed that the fluorescence intensity was significantly higher in ATM2759 transfected CHO cells than in those transfected with ATN. CONCLUSIONS: Leu99Phe substitution may not affect the binding capacity of AT with heparin. Secretion defect and intracellular accumulation of the mutated AT protein might be the mechanisms of this mutation causing AT deficiency.

Characterization of molecular defect of 13387-9delG mutated antithrombin in inherited type I antithrombin deficiency.

As a major physiological inhibitor of thrombin and other coagulation proteases, antithrombin (AT) plays an important role in the maintenance of normal hemostasis and its deficiency is associated with a predisposition for familial venous thromboembolic disease. Recently, we found a novel mutation (13387-9delG) in the antithrombin gene that is associated with type I AT deficiency. To examine the molecular pathologic mechanism of this mutation causing type I AT deficiency, the wild-type and the mutant AT constructs were expressed in COS-7 cells or Chinese Hamster Ovary cells. No AT antigen could be detected by enzyme-linked immunosorbent assay in the conditioned media of cells expressing the mutant protein, and the AT antigen level was reduced in cell lysates. The mutant AT-expressing cells did not have less intracellular mRNA levels than the wild-type transfectants as estimated by quantitative reverse transcriptase-polymerase chain reaction. Metabolic and pulse-chase experiments showed the newly synthesized wild-type AT protein was gradually secreted into the media, whereas no labeled mutant AT protein was detected in the media and the total amount of radioactivity was significantly reduced in the cells during the chase periods. By immunofluorescence analysis, the staining of the mutant AT was weaker than that of the wild type, and was predominantly diffuse without perinuclear enhancement. These results indicate that the 13387-9delG mutation, which disrupts the disulfide bridge Cys247-Cys430, impairs the secretion and stability of the truncated AT protein associated with intracellular degradation.

[A heterozygous point mutation G13328A in antithrombin gene causes thrombosis].

OBJECTIVE: To identify the phenotype and the gene mutation in a kindred with antithrombin (AT) deficiency. METHODS: Immuno-nephelometry and chromogenic assay were used to detect the plasma level of AT antigen (AT: Ag) and activity (AT: A), respectively. All the seven exons and intron-exon boundaries of AT gene from the propositus were amplified by PCR and direct sequencing of the PCR pro-ducts was performed. Corresponding PCR fragments from the kindred were also sequenced directly. Megaprimer method was used to construct the mutant AT cDNA expressing vector from normal plasmid pCRII AT cDNA. The normal and mutant AT plasmid were transiently transfected into Cos-7 cells and AT: Ag was detected in supernatant and lysate of transfected cell with ELISA. RESULTS: The plasma level of AT: Ag and AT: A for the propositus were 179 mg/L and 42.3%, respectively. A heterozygous G13328A missense mutation in exon 6 was identified, which led to the substitution of Thr (ACC) 404 for Ala (GCC). The sequencing results from the pedigree suggested that three other members also had the mutation. The level of AT:Ag in supernatant and lysate from cells transfected with mutant AT cDNA was 40% and 68% of that of normal AT cDNA transfected cells. CONCLUSION: This is an unreported AT gene mutation in China, which causes type I hereditary antithrombin deficiency and thrombosis in the proposita.