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Biomedical subjects

U Seligsohn

Publications and source records attributed to U Seligsohn.

At least 55 records · Page 3Linked to original sources
PubMed1999

Single and combined prothrombotic factors in patients with idiopathic venous thromboembolism: prevalence and risk assessment.

The inherited thrombophilias--deficiencies of protein C, protein S, and antithrombin III--and the prothrombotic polymorphisms factor V G1691A and factor II G20210A predispose patients toward venous thromboembolism (VTE). The aim of this study was to determine the prevalence of single and combined prothrombotic factors in patients with idiopathic VTE and to estimate the associated risks. The study group consisted of 162 patients referred for work-up of thrombophilia after documented VTE. The controls were 336 consecutively admitted patients. In all subjects factor V G1691A, factor II G20210A, and methylenetetrahydrofolate reductase (MTHFR) C677T were analyzed by specific polymerase chain reactions and restriction enzymes. Activities of antithrombin III and protein C, free protein S antigen, and lupus anticoagulant were determined in a subset of 109 patients who were not receiving oral anticoagulants. The prevalences of heterozygotes and homozygotes for factor V G1691A and factor II G20210A among patients and controls were 40.1% versus 3.9% and 18.5% versus 5.4%, respectively (P=0.0001). The prevalence of homozygotes for MTHFR C677T in patients was 22.8% and in controls, 14.3% (P=0.025). Heterozygous and homozygous factor V G1691A, factor II G20210A, and homozygous MTHFR C677T were found to be independent risk factors for VTE, with odds ratios of 16.3, 3.6, and 2.1, respectively. Two or more polymorphisms were detected in 27 of 162 patients (16.7%) and in 3 of 336 controls (0.9%). Logistic regression analysis disclosed odds ratios of 58.6 (confidence interval [CI], 22.1 to 155.2) for joint occurrence of factor V and factor II polymorphisms, of 35.0 (CI, 14.5 to 84.7) for factor V and MTHFR polymorphisms, and of 7.7 (CI, 3.0 to 19.6) for factor II and MTHFR polymorphisms. Among 109 patients in whom a complete thrombophilic work-up was performed, 74% had at least 1 underlying defect. These data indicate that in most patients referred for evaluation of thrombophilia due to idiopathic VTE, 1 or more underlying genetic predispositions were discernible. The presence of >1 of the prothrombotic polymorphisms was associated with a substantial risk of VTE.

Adult↗
PubMed1999

Mendelian diseases among Roman Jews: implications for the origins of disease alleles.

The Roman Jewish community has been historically continuous in Rome since pre-Christian times and may have been progenitor to the Ashkenazi Jewish community. Despite a history of endogamy over the past 2000 yr, the historical record suggests that there was admixture with Ashkenazi and Sephardic Jews during the Middle Ages. To determine whether Roman and Ashkenazi Jews shared common signature mutations, we tested a group of 107 Roman Jews, representing 176 haploid sets of chromosomes. No mutations were found for Bloom syndrome, BRCA1, BRCA2, Canavan disease, Fanconi anemia complementation group C, or Tay-Sachs disease. Two unrelated individuals were positive for the 3849 + 10C->T cystic fibrosis mutation; one carried the N370S Gaucher disease mutation, and one carried the connexin 26 167delT mutation. Each of these was shown to be associated with the same haplotype of tightly linked microsatellite markers as that found among Ashkenazi Jews. In addition, 14 individuals had mutations in the familial Mediterranean fever gene and three unrelated individuals carried the factor XI type III mutation previously observed exclusively among Ashkenazi Jews. These findings suggest that the Gaucher, connexin 26, and familial Mediterranean fever mutations are over 2000 yr old, that the cystic fibrosis 3849 + 10kb C->T and factor XI type III mutations had a common origin in Ashkenazi and Roman Jews, and that other mutations prevalent among Ashkenazi Jews are of more recent origin.

Alleles↗
PubMed1999

Risk factors associated with postpartum ovarian vein thrombosis.

Thrombosis of the ovarian vein is a remarkable process occuring within a few days of labor in 1:500-1:2000 women. Its presentation is characterized by fever, abdominal pain and occasionally by a palpable abdominal mass that in earlier years sometimes lead to explorative laparotomy. With the advent of modern imaging techniques the diagnosis can be made relatively easily. The pathogenesis has been attributed to an infectious process expanding from the uterus to the right ovarian vein and stasis. A predisposition towards thrombosis has not been so far explored. In this study we retrospectively analysed the clinical features, diagnosis and treatment of 22 patients with objective documentation of post partum ovarian vein thrombosis (POVT) and assessed potential risk factors. In 11 of the 22 patients (50%) inherited prothrombotic risk factors were detected as follows: 4 were heterozygous for factor V G1691A, 2 had protein S deficiency, one had protein S deficiency and was heterozygous for factor V G1691A, and 4 were homozygous for MTHFR C677T. Eight of the 11 patients who bore a prothrombotic predisposition underwent cesarean section. Taken together, the data suggest that POVT may result from the combined effect of an infection, cesarean section and a prothrombotic tendency.

Adult↗
PubMed1998

A single genetic origin for the common prothrombotic G20210A polymorphism in the prothrombin gene.

The polymorphism G20210A in the 3' untranslated region of the prothrombin gene is associated with an increased level of factor II activity and confers a twofold to fivefold increase in the risk for venous thromboembolism. Among Caucasian populations, the prevalence of factor II G20210A heterozygotes is 1% to 6%, whereas in non-Caucasian populations it is very rare or absent. The aim of the present study was to discern whether factor II G20210A originated from a single or recurrent mutational events. Allele frequencies of four dimorphisms spanning 16 of 21 kb of the factor II gene were determined in 133 unrelated Caucasian subjects of Jewish, Austrian, and French origins who bore factor II G20210A (10 homozygotes and 123 heterozygotes) and 110 Caucasian controls. Remarkable differences in the allele frequencies for each dimorphism were observed between the study groups (P = .0007 or less), indicating strong linkage disequilibrium and suggesting a founder effect. Indeed, a founder haplotype was present in 68% of 20210A mutant alleles and only in 34% of 20210G normal alleles (P < .0001). These data strongly support a single origin for factor II G20210A that probably occurred after the divergence of Africans from non-Africans and of Caucasoid from Mongoloid subpopulations.

Africa, Northern↗
PubMed1998

Mutations in the ER-Golgi intermediate compartment protein ERGIC-53 cause combined deficiency of coagulation factors V and VIII.

Combined deficiency of factors V and VIII is an autosomal recessive bleeding disorder resulting from alterations in an unknown gene on chromosome 18q, distinct from the factor V and factor VIII genes. ERGIC-53, a component of the ER-Golgi intermediate compartment, was mapped to a YAC and BAC contig containing the critical region for the combined factors V and VIII deficiency gene. DNA sequence analysis identified two different mutations, accounting for all affected individuals in nine families studied. Immunofluorescence and Western analysis of immortalized lymphocytes from patients homozygous for either of the two mutations demonstrate complete lack of expression of the mutated gene in these cells. These findings suggest that ERGIC-53 may function as a molecular chaperone for the transport from ER to Golgi of a specific subset of secreted proteins, including coagulation factors V and VIII.

Amino Acid Sequence↗
PubMed1998

Association between hyperflexibility of the thumb and an unexplained bleeding tendency: is it a rule of thumb?

A bleeding tendency manifested by petechiae and ecchymoses is one of the most common causes for referral of patients to haematology clinics. Vessel wall pathology is not usually considered to be a cause for deranged haemostasis, although coexistence of increased capillary fragility and joint hypermobility have been reported. We determined the frequency of thumb hyperextensibility and scored the findings in a series of 44 patients referred because of ecchymoses and petechiae, as well as 261 control children and their mothers. All 44 patients had normal coagulation studies. Thumb flexibility score was +4 in 30 patients, +3 in eight patients, +2 in five patients and +1 in one of the index patients. In the control group, only one of 261 had a +4, and three had a +3 score, and two of 260 mothers had a +4 score. Ecchymoses were not observed in any of these subjects, nor in the +1 patients. Based on clinical presentation and normal coagulation studies, we suggest that our patients had an underlying subtype of Ehlers-Danlos syndrome. In view of the dramatically high occurrence of thumb hyperextensibility in patients with unexplained mild bleeding tendency, costly haemostatic and coagulation studies on such patients may not be necessary.

Child↗
PubMed1998

Prenatal diagnosis of Glanzmann thrombasthenia using the polymorphic markers BRCA1 and THRA1 on chromosome 17.

Glanzmann thrombasthenia is an autosomal recessive bleeding disorder caused by mutations in the genes encoding platelet GPIIb or GPIIIa. Both genes map to chromosome 17q21 and polymorphisms within this chromosomal region have been identified. In the current study, prenatal diagnosis was performed for a family that already had one affected child, patient 1, who had a compound heterozygous mutation in GPIIb. At the time of prenatal diagnosis, the maternal GPIIb mutation had been identified but the paternal GPIIb mutation was unknown. By sequence analysis, the fetus was identified as a carrier of the mother's mutation. To determine the probability of the fetus inheriting the father's mutation, haplotype analysis of DNA samples from the fetus, mother, father and affected child were performed using polymorphic markers on chromosome 17q12-q21. These markers included polymorphisms within the thyroid hormone receptor alpha1 gene (THRA1), the breast cancer gene (BRCA1), GPIIb, GPIIIa, and an anonymous marker D17S579. Heterozygosity within the THRA1, BRCA1 and GPIIIa polymorphic markers predicted that the fetus carried the father's normal allele. Based on genetic linkage studies, no recombination was identified with any of the informative markers, and from the map distance between GPIIb and BRCA1 the accuracy of diagnosis was predicted to be >98%. The father's mutation was subsequently identified and direct sequence analysis of fetal DNA confirmed that the fetus did not inherit the fathers' mutant allele.

BRCA1 Protein↗
PubMed1998

Combined factors V and VIII deficiency--the solution.

Combined deficiency of coagulation factor V and factor VIII is an autosomal recessive disorder which has been observed in a number of populations around the world. However, this disease appears to be most common in the Mediterranean basin, particularly in Jews of Sephardic and Middle Eastern origin living in Israel. We have taken a positional cloning approach toward identifying the gene responsible for this disorder. We initially studied 14 affected individuals from nine unrelated Jewish families using a panel of polymorphic genetic markers spaced throughout the human genome. The combined factors V and VIII deficiency gene was mapped to a locus on the long arm of chromosome 18 with a maximal LOD score of 13.22. A detailed genetic analysis identified two distinct haplotypes among these families, suggesting two independent founders or, alternatively, a single ancient founder with a more recent split of these subpopulations. Further work to identify and characterize the gene responsible for combined factors V and VIII deficiency should provide important insights into the biosynthesis of these homologous proteins.

Chromosome Mapping↗
PubMed1998

Glanzmann thrombasthenia in two Iraqi-Jewish siblings is caused by a novel splice junction mutation in the glycoprotein IIb.

An A-->G transition in the acceptor splice site at the intron 19/exon 20 junction of the glycoprotein IIb gene was defined as a novel mutation causing Glanzmann thrombasthenia in two Iraqi-Jewish siblings. This mutant DNA was transcribed into four distinct species of mRNA, one of which resulted in a premature termination codon and the other three predicting deletions of 50, 61 or 72 amino acids, respectively.

Aged↗
PubMed1998

Analysis of genetic polymorphisms related to thrombosis and other risk factors in patients with retinal vein occlusion.

The purpose of this study was to investigate the role of genetic polymorphisms associated with venous and arterial thrombosis in patients with retinal vein occlusion (RVO). One-hundred and two consecutive patients with RVO were examined for factor V G1691A and factor II G20210A, methylenetetrahydrofolate reductase (MTHFR) C677T and apolipoprotein E4 by amplification of specific DNA fragments and restriction analysis. The risks exerted by these polymorphisms and by the conventional risk factors of RVO were evaluated by comparing their frequencies among patients and controls and by estimating the respective odds ratios. We found that the prevalences of the factor V G1691A, factor II G20210A, and apolipoprotein E4 polymorphisms were similar in the study and control groups. Logistic regression analysis involving the parameters for which significant differences were detected disclosed an odds ratio of 1.9 for MTHFR C677T homozygosity (95% confidence interval 0.95-3.81), an odds ratio of 2.12 for hypertension (95% confidence interval 1.16-3.73) and an odds ratio of 3.25 for a family history of stroke (95% confidence interval 1.07-9.51). Our data suggests that homozygosity for the MTHFR C677T polymorphism is a risk factor of RVO in addition to arterial hypertension and a family history of stroke.

Adult↗
PubMed1998

Mutations in the alphaIIb and beta3 genes that cause Glanzmann thrombasthenia can be distinguished by a simple procedure using transformed B-lymphocytes.

Glanzmann thrombasthenia (GT) is caused by a defect in either glycoprotein (GP)IIb (alphaIIb) or GPIIIa (beta3) genes and therefore screening of both genes is required for mutation identification. The beta subunit of the GPIIb/IIIa complex (beta3) forms a complex with another alpha subunit (alpha(v)) yielding the alpha(v)beta3 vitronectin receptor (VnR). GT patients with mutations in the GPIIIa gene that cause diminished synthesis of GPIIIa are deficient in both GPIIb/IIIa and VnR, whereas patients with mutations in the GPIIb gene are deficient in GPIIb/IIIa, yet express normal or increased VnR in their platelets. The presence or absence of VnR in platelet membranes of GT patients has therefore been used for distinguishing between mutations in the GPIIb gene and mutations in the GPIIIa gene. However, the method of assessing VnR in platelets is cumbersome and use of fresh platelets is indispensible. In the present work we devised a procedure for detection of the VnR in B-lymphocytes transformed by Epstein-Bar virus (EBV). The transformed lymphocytes transcribed GPIIIa mRNA but not GPIIb mRNA and expressed VnR on their surface. Using flow cytometry analysis or immuno-precipitation and western blotting VnR was found in B-lymphocytes of GT patients bearing a well characterized mutation in the GPIIb gene. In contrast, in B-lymphocytes of GT patients bearing 2 different mutations in the GPIIIa gene no VnR was detectable. Thus, for determining which gene is mutated in a GT patient, EBV-transformed B-lymphocytes are useful and can as well be used for analyses of GPIIIa mRNA and genomic DNA. Ten ml of blood are sufficient for the procedure.

B-Lymphocytes↗
PubMed1997

The two common mutations causing factor XI deficiency in Jews stem from distinct founders: one of ancient Middle Eastern origin and another of more recent European origin.

Previous studies showed that factor XI (FXI) deficiency commonly observed in Ashkenazi Jews is caused by two similarly frequent mutations, type II (Glu117stop) and type III (Phe283Leu) with allele frequencies of 0.0217 and 0.0254, respectively. In Iraqi Jews, who represent the ancient gene pool of Jews, only the type II mutation was observed with an allele frequency of 0.0167. In this study we sought founder effects for each mutation by examination of four FXI gene polymorphisms enabling haplotype analysis in affected Jewish patients of Ashkenazi, Iraqi, and other origins and in Arab patients. Initial population surveys of 387 Middle Eastern Jews (excluding Iraqi Jews), 560 North African/Sephardic Jews, and 382 Arabs revealed allele frequencies for the type II mutation of 0.0026, 0.0027, and 0.0065, respectively. In contrast, the type III mutation was not detected in any of these populations. All 60 independent chromosomes bearing the type III mutation were solely observed in Ashkenazi Jewish patients and were characterized by a relatively rare haplotype. All 103 independent chromosomes bearing the type II mutation in patients of Ashkenazi, Iraqi, Yemenite, Syrian, and Moroccan Jewish origin and of Arab origin were characterized by another distinct haplotype that was rare among normal Ashkenazi Jewish, Iraqi Jewish, and Arab chromosomes. These findings constitute the first example of a mutation common to Ashkenazi Jews, non-Ashkenazi Jews, and Arabs and are consistent with the origin of type II mutation in a founder before the divergence of the major segments of Jews. Our findings also indicate that the type III mutation arose more recently in an Ashkenazi Jewish individual.

Africa, Northern↗
PubMed1997

Glanzmann thrombasthenia caused by an 11.2-kb deletion in the glycoprotein IIIa (beta3) is a second mutation in Iraqi Jews that stemmed from a distinct founder.

Glanzmann thrombasthenia (GT) is a rare bleeding disorder resulting from mutations in either glycoprotein (GP) IIb or GPIIIa genes. The disease is relatively frequent in highly inbred populations such as Iraqi Jews. The molecular basis of GT in 6 unrelated Iraqi-Jewish patients was previously identified as an 11-bp deletion in exon 12 of the GPIIIa gene. We now describe a second mutation found in 3 unrelated Iraqi-Jewish families that consists of an 11.2-kb deletion between an Alu repeat in intron 9 and exon 13 of the GPIIIa gene. The mutant DNA is transcribed into mRNA in which exons 10 through 13 are absent. Splicing of exon 9 directly to exon 14 leads to a shift in the reading frame resulting in a stop codon. The predicted protein is truncated in the middle of the third cysteine-rich domain before the transmembrane domain. Simple DNA-based methods were devised for identification of both mutations in Iraqi Jews for the purpose of carrier detection and prenatal diagnosis enabling prevention of GT. A survey of the general Iraqi-Jewish population for the first 11-bp deletion and the second 11.2-kb deletion disclosed that the allele frequency of the first mutation was 0.0043, whereas none of 700 individuals examined bore the second mutation (allele frequency <0.0007). Among 40 GT patients of Iraqi-Jewish origin 31 were homozygous for the first mutation, 4 were compound heterozygotes for the first and second mutations, and 2 were homozygous for the second mutation. Haplotype analyses using 4 polymorphic markers in the GPIIIa gene showed that each mutation originated in a distinct founder.

Adult↗
PubMed1997

Linkage of combined factors V and VIII deficiency to chromosome 18q by homozygosity mapping.

Combined Factors V and VIII deficiency is an autosomal recessive bleeding disorder identified in at least 58 families comprising a number of different ethnic groups. Affected patients present with a moderate bleeding tendency and have Factor V and Factor VIII levels in the range of 5-30% of normal. The highest frequency of the mutant gene is found in Jews of Sephardic and Middle Eastern origin living in Israel with an estimated disease frequency of 1:100,000. We sought to identify the gene responsible for combined Factors V and VIII deficiency using a positional cloning approach. Of 14 affected individuals from 8 unrelated Jewish families, 12 were the offspring of first-cousin marriages. After a genome-wide search using 241 highly polymorphic short tandem repeat (STR) markers, 13 of the 14 affected patients were homozygous for two closely linked 18q markers. Patients and all available family members were genotyped for 11 additional STRs spanning approximately 11 cM on the long arm of chromosome 18. Multipoint linkage analysis yielded a maximal log of the odds (LOD) score of 13.22. Haplotype analysis identified a number of recombinant individuals and established a minimum candidate interval of 2.5 cM for the gene responsible for combined Factors V and VIII deficiency. The product of this locus is likely to operate at a common step in the biosynthetic pathway for these two functionally and structurally homologous coagulation proteins. Identification of this gene should provide new insight into the biology of Factor V and Factor VIII production.

Chromosome Mapping↗
PubMed1997

A single genetic origin for a common Caucasian risk factor for venous thrombosis.

A common genetic risk factor for venous thrombosis among Caucasoid subpopulations is a polymorphism, nt G1691A, in blood coagulation factor V that replaces Arg506 with Gln and imparts resistance of factor Va to the anticoagulant, activated protein C. Haplotype analyses using six dimorphic sites in the factor V gene for 117 Caucasian subjects of Jewish, Arab, Austrian, and French origin who were homozygous for nt A1691 compared with 167 controls (nt G1691) support a single origin for this polymorphism. The nt G1691A mutation is estimated to have arisen circa 21,000 to 34,000 years ago, ie, after the evolutionary divergence of Africans from non-Africans and of Caucasoid from Mongoloid subpopulations.

Arginine↗
PubMed1997

Acquired von Willebrand disease in a patient with angiodysplasia resulting from immune-mediated clearance of von Willebrand factor.

A patient with a severe bleeding tendency due to acquired von Willebrand disease (VWD) is presented. Although no underlying disorder has emerged during 6 years of follow-up, an immune-mediated mechanism was responsible for acquired VWD in this patient as demonstrated by detection of von Willebrand factor (VWF)/anti-VWF complexes in the patient's plasma and their removal by protein A-sepharose beads and resumption of normal haemostasis with correction of VWF antigen, VWF activity and VWF multimeric pattern after treatment of the patient with high-dose gammaglobulin. Detection of anti-VWF antibodies in the patient's plasma had a significant impact on the choice of therapeutic intervention to control bleeding.

Angiodysplasia↗
PubMed1997

Bleeding predictors in factor-XI-deficient patients.

Bleeding in factor-XI-deficient patients is mainly injury-related. Parameters influencing bleeding particularly in patients with minor factor XI deficiency have not been defined. We utilized a logistic regression model to analyze parameters influencing bleeding tendency in subjects from 45 families with factor XI deficiency. Bleeding manifestations were documented in 58% of 26 homozygous or doubly heterozygous factor-XI-deficient patients, in 20% of 46 heterozygous factor-XI-deficient patients and in 9% of 47 family members with a normal factor XI genotype. Odds ratios for bleeding in homozygotes or double heterozygotes were 13 and in heterozygotes 2.6 with 95% confidence intervals of 3.8-45 and 0.8-9.0, respectively. Bleeding correlated negatively with factor XI level (r = -0.36, P = 0.0001) with major factor XI deficiency being a strong predictor of bleeding (P = 0.011). Minor factor XI deficiency and blood group O slightly contributed to bleeding. Although factor VIII and factor XI levels were correlated (r = 0.48, P = 0.0001), levels of factor VIII and von Willebrand factor were not predictors of bleeding. Bleeding was more common following operative procedure involving mucosal membranes (P < 0.01). The designed model enabled prediction of bleeding manifestations with an overall accuracy of 78% and 82% in heterozygotes.

Case-Control Studies↗