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Biomedical subjects

G Castaman

Publications and source records attributed to G Castaman.

At least 37 records · Page 2Linked to original sources
PubMed2001

Congenital absence of the inferior vena cava: a rare risk factor for idiopathic deep-vein thrombosis.

Congenital absence of the inferior vena cava (AIVC) is a rare vascular defect, commonly reported as a fortuitous finding. The presence of AIVC in patients with DVT is underestimated because AIVC cannot be detected by compression B-mode ultrasonography. By use of computed tomography, we diagnosed four cases of AIVC in young patients with idiopathic DVT over a 5 year period. Based on the occurrence of DVT in patients below 30 years in our area during the same period, we estimate that AIVC is present in about 5% of cases of DVT in young patients. Computed tomography or angiography should be used for the diagnosis of idiopathic DVT in young patients.

Adolescent↗
PubMed2001

Novel Y283C mutation of the A subunit for coagulation factor XIII: molecular modelling predicts its impaired protein folding and dimer formation.

In an Italian patient with severe factor XIII deficiency, a novel mutation, Y283C (TAT to TGT), was identified heterozygously by nucleotide sequencing analysis in exon VII of the gene for the A subunit. The presence of this mutation was confirmed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis in the proband and his brother. Molecular modelling predicts that the mutant molecule would be misfolded. It is probable that the impaired folding of the mutant Y283C A subunit led to its instability, which is at least in part responsible for the factor XIII deficiency of this patient.

Child↗
PubMed2001

Congenital von Willebrand disease type I: definition, phenotypes, clinical and laboratory assessment.

Von Willebrand disease, with a prevalence of about 1% in the general population, is the most frequent inherited bleeding disorder. Among the major subtypes, type I von Willebrand disease represents by far the more prevalent category (about 70%) and includes cases with a partial deficiency of plasma von Willebrand factor and no evidence of qualitative defects. The clinical expression as well as the laboratory phenotype of the disorder and its penetrance are greatly variable. The diagnosis usually requires the presence of autosomally inherited bleeding history co-segregating with a low von Willebrand factor level. The influence of several genetic and acquired conditions on the level of von Willebrand factor is however, widely appreciated and represents the major obstacle in correctly identifying von Willebrand disease as the cause of a bleeding diathesis in several families. The molecular genetics of the minority of cases showing high penetrance and expressivity of the phenotype are unravelling, but for the large majority of milder cases, the molecular basis is still unknown. We present a practical approach to diagnosis, based on scientific evidence and direct experience. The implications of the diagnosis of von Willebrand disease for the patient's quality of life are also considered.

Clinical Laboratory Techniques↗
PubMed2001

Phenotypic APC resistance in carriers of the A20210 prothrombin mutation is associated with an increased risk of venous thrombosis.

We hypothesized that increased prothrombin levels associated with G20210A prothrombin gene mutation could affect the results of activated protein C (APC) resistance phenotype and increase the risk of venous thrombosis (VT). The increasing addition of purified prothrombin in plasma of 90 normal subjects resulted in a parallel significant increase of APC resistance. Significantly different mean n-APC-SR in 879 GG20210 subjects compared to 27 heterozygous carriers of isolated G20210A mutation was observed (1.0 +/- 0.12 vs. 0.95 +/- 0.11; P = 0.02) in a random sample of 906 normal population subjects. Twenty-seven families with VT and isolated G20210A mutation consecutively diagnosed during 1998-1999 were evaluated. Mean n-APC-SR was significantly lower in the 80 G20210A carriers compared to 58 GG 20210 relatives investigated, even after sex and age adjustment (0.92 +/- 0.08 vs. 1.05 +/- 0.13; P < 0.0001). A strong relationship between plasma prothrombin level and n-APC-SR was observed in the families. When n-APC-SR values were grouped in tertiles, the odds ratio for VTE, after exclusion of the index cases and adjustment for 20210 status, for subjects in the lowest tertile (n-APC-SR 0.73-0.90) was 4.58 (95% CI 0.78-26.88) compared to upper tertile (n-APC-SR 1.01-1.30). In conclusion, in subjects with G20210A mutation APC resistance is significantly increased, correlates with plasma prothrombin level and the carriers with the lowest APC resistance values have an increased risk of VTE.

3' Untranslated Regions↗
PubMed2000

Heightened proteolysis of the von Willebrand factor subunit in patients with von Willebrand disease hemizygous or homozygous for the C2362F mutation.

We studied the proteolytic pattern of the mutant von Willebrand factor (VWF) in four patients with von Willebrand disease (VWD) who were either homozygous or hemizygous for the mutation C2362F. A significant decrease in the native fragment of 225 kDa was evident in all the patients, together with a marked increase in the 176 and 140 kDa fragments, a pattern usually observed in type 2A VWD. The proteolytic pattern measured in four heterozygotes for C2362F was within the normal range, suggesting that the mutant VWF C2362F present in the plasma of these patients may be protected from proteolysis by normal VWF.

Genotype↗
PubMed2000

Early haemorrhagic morbidity and mortality during remission induction with or without all-trans retinoic acid in acute promyelocytic leukaemia.

A total of 622 consecutive patients with acute promyelocytic leukaemia (APL) treated within the Gruppo Italiano per le Malattie Ematologiche dell'Adulto (GIMEMA) group during 1989-97 have been reviewed to assess the clinical effectiveness of all-trans retinoic acid (ATRA) on the incidence of early haemorrhagic deaths and on APL-associated coagulopathy. Of them, 499 were treated with idarubicin plus ATRA (study A) and 123 with Idarubicin alone (study B). In both studies, similar guidelines for supportive treatment were used. Haemorrhagic symptoms were evaluated according to a reproducible score system. Deaths occurring within 10 d of starting treatment were 19 (3.8%) in study A and nine (7.3%) in study B (P = 0.09), with 15 (3%) and five (4.1%) (P not significant) due to haemorrhage. Overall, induction mortality was 7.6% and 16.2% respectively (P < 0.003). In study A, days with platelet counts </= 20 x 109/l or with fibrinogen </= 1 g/L were reduced by about 30%, the haemorrhagic score by 50% and the consumption of blood products by about 40%, and fewer patients were treated with antihaemorrhagic drugs (39% vs. 61%; P < 0.001). On multivariate analysis, early deaths were influenced by blast count at diagnosis > 30 x 109/l (P < 0.001) in both studies, and by a haemorrhagic score of 3 in study A (P < 0.001). Although the reduction of early fatal haemorrhages was not significant, a substantial clinical improvement was evident in terms of reduction of the severity of bleeding symptoms, blood product consumption and overall induction mortality when ATRA was combined with idarubicin.

Adolescent↗
PubMed2000

Autosomal dominant type 1 von willebrand disease due to G3639T mutation (C1130F) in exon 26 of von Willebrand factor gene: description of five Italian families and evidence for a founder effect.

Twenty-four apparently unrelated Italian patients with autosomal dominant type 1 von Willebrand disease (VWD) and a clear autosomal pattern of inheritance of bleeding symptoms were screened for the C1149R and C1130F mutations. None of the patients had the C1149R mutation; three patients and four affected relatives were heterozygous for the C1130F mutation. The mutation appeared to be linked to a single haplotype, defined by five genetic markers [variable number tandem repeat (VNTR) I and II in intron 40, RsaI in exons 13 and 18 and HphI in exon 28], suggesting a founder effect. The patients responded well to desmopressin infusion. The C1130F mutation might have a dominant negative effect on the secretion of the normal protein that desmopressin would appear to overcome.

Deamino Arginine Vasopressin↗
PubMed2000

The risk of venous thromboembolism in family members with mutations in the genes of factor V or prothrombin or both.

Factor V Leiden and the G20210A mutation in the prothrombin gene are the most frequent abnormalities associated with venous thromboembolism. It is unknown whether the risks due to the presence of either mutation are of the same magnitude. We compared the prevalence and incidence rate of venous thromboembolism in relatives with either mutation or both. The finding of different rates might influence the strategies for primary prevention of thrombosis in carriers of these mutations. The study population included 1076 relatives of probands with the prothrombin gene mutation, factor V Leiden or both who underwent screening for inherited thrombophilia and were found to be carriers of single mutations or double mutations or who were non-carriers. The prevalence of venous thromboembolism was 5.7% in relatives with the prothrombin gene mutation, 7.8% in those with factor V Leiden, 17.1% in those with both mutations and 2.5% in non-carriers. Annual incidences of thrombosis were 0.13% [95% confidence interval (CI) 0.06-0.24], 0.19% (0.13-0.25), 0.42% (0.15-0.83) and 0.066% (0.03-0.11), respectively, and the relative risk of thrombosis was two times higher in carriers of the prothrombin gene mutation, three times higher in those with factor V Leiden and six times higher in double carriers than in non-carriers. The incidence of venous thromboembolism in carriers of the prothrombin gene mutation is slightly lower than that observed in carriers of factor V Leiden, whereas in carriers of both mutations it is two or three times higher. These findings suggest that lifelong primary anticoagulant prophylaxis of venous thromboembolism is not needed in asymptomatic carriers of single or double mutations. Anticoagulant prophylaxis seems to be indicated only when transient risk factors for thrombosis coexist with mutations.

Adolescent↗
PubMed2000

The A20210 allele in the prothrombin gene enhances the risk of venous thrombosis in carriers of inherited protein S deficiency.

Sixteen families with inherited protein S deficiency and venous thromboembolism (VT) were screened for the presence of factor V (FV) Leiden mutation and for the G20210A allele in the prothrombin gene. While FV Leiden was not detected in any of the families, protein S deficiency and prothrombin mutation were present in five families. To assess the risk of VT in carriers of the combined defects, a total of 92 members of the 16 families, including propositi, were examined. Thirty subjects were normal, 40 showed protein S deficiency, 10 the prothrombin mutation and 12 showed both abnormalities. When index cases were excluded, thrombosis history were present in 40.7% of protein S-deficient patients, 75% of patients with combined abnormality, one out of the 10 (10%) with prothrombin mutation and only one (3.3%) of the normal subjects. Relatives with combined defects showed the highest incidence rate of VT in comparison with normal relatives (rate ratio = 32.4), those with protein S deficiency an intermediate degree (rate ratio = 15.7), and G20210A relatives the lowest (rate ratio = 3.4). Relatives with combined defects had an increased risk of VT in comparison with relatives with protein S deficiency (incidence rate ratio 2.1; 95% confidence interval, 0.7-5.41; P = 0.1). In conclusion, the presence of the prothrombin mutation seems to increase the risk of VT carriers of protein S deficiency, although additional families are required to fully estimate the magnitude of risk.

Adult↗
PubMed2000

Von Willebrand Disease type 2M "Vicenza" in Italian and German patients: identification of the first candidate mutation (G3864A; R1205H) in 8 families.

Von Willebrand disease type 2M "Vicenza" (VWD 2M V) is characterised by autosomal dominant inheritance, low von Willebrand factor (VWF) and the presence of "supranormal" multimers in plasma. This specific phenotype has been described in Italian and recently also in German patients. The molecular defect is linked to the VWF gene. However, no specific mutations have been identified until now. We analysed the complete coding region and adjacent intron sequences of the VWF gene in Italian families in comparison to German families with VWD 2M V by a PCR-based mutation screening, combined with SSC- and heteroduplex-analysis of exons 2 through 52, followed by direct sequencing. We identified the first heterozygous candidate mutation (G3864A; R1205H) in all affected members of the 7 Italian families and in 1 German patient but not in the unaffected family members nor on 100 chromosomes of normal subjects, suggesting a causal relationship between the mutation and the phenotype. Haplotype identity, with minor deviations in one Italian family, suggests a common but not very recent genetic origin of R1205H.

Female↗
PubMed2000

The VITA Project: heritability of resistance to activated protein C. Vincenza Thrombophilia and Arteriosclerosis.

Resistance to activated protein C (APC) is a risk factor for venous thromboembolism also in absence of the FV Leiden mutation. To evaluate the influence of genetic factors on APC resistance, we evaluated the heritability of the APC resistance phenotype in 1,519 sib-parent pairs randomly selected from the VITA Project. After adjustment for known influencing factors, a high heritability coefficient (0.58) was observed and parental response to APC was the single most important factor in predicting the corresponding phenotype in sibs. In 32 parent-sib pairs in which phenotypic resistance to APC unrelated to FV Leiden was present in both parents and sibs, no additional mutation on the 306-aminoacid residue of FV (FV Cambridge and FV Hong Kong) was found. In these 32 parent-sib pairs, FVIII:C and vWf:Ag levels were not significantly increased and there was no excess prevalence of the R2 allele of exon 13 of FV gene. This study suggests that the response to APC is significantly influenced by genetic factors also at a population level, but the responsible mechanisms are still undefined.

Activated Protein C Resistance↗
PubMed1999

Coinheritance of the HR2 haplotype in the factor V gene confers an increased risk of venous thromboembolism to carriers of factor V R506Q (factor V Leiden).

With the aim of establishing whether the HR2 haplotype in factor V affects the risk of venous thromboembolism, a retrospective multicenter cohort study was performed in 810 family members identified through 174 probands who suffered from at least 1 episode of deep vein thrombosis and/or pulmonary embolism and had an inherited defect associated with thrombophilia (antithrombin, protein C, or protein S deficiency; factor V R506Q or prothrombin G20210A). Fifty-eight percent (468/810) of the family members had an inherited defect and 10% (47/468) were symptomatic. The HR2 haplotype was found in association with factor V R506Q more frequently in family members with venous thromboembolism (18%) than in those without (8%). Double heterozygosity for factor V R506Q and HR2 conferred a 3- to 4-fold increase in the relative risk of venous thromboembolism compared with factor V R506Q alone. The median age at first event was lower when the 2 defects were associated (46 v 52 years). No increase in risk of venous thromboembolism could be demonstrated when the HR2 haplotype was associated with inherited thrombophilic defects other than factor V R506Q. Because both factor V R506Q and the HR2 haplotype are very frequent, the effect of their coinheritance on the risk of venous thromboembolism might represent a clinically relevant issue, and screening for HR2 in carriers of factor V R506Q should be considered.

Adolescent↗