Factor V Leiden Mutation in the Argentinian Population

Humans, mice, and mechanisms of intestinal atresias: a window into understanding early intestinal development

INTRODUCTION

Intestinal atresias have long been hypothesized to result from either failure of recanalization of the intestinal lumen or in utero vascular accidents. Recent work in animal models is now calling for a reassessment of these widely held paradigms.

PURPOSE

In this review, we will examine the data that led to the original hypotheses and then evaluate more recent work challenging these hypotheses. Furthermore, we will discuss how defining the mechanism of atresia formation in animal models may provide insight into early intestinal development and the mechanism of lengthwise intestinal growth.

CONCLUSION

Such insight will be critical in developing regenerative therapies for patients with intestinal failure.

Factor V Leiden and the risk of venous thrombosis, myocardial infarction, and stroke: a case-control study in Venezuela

The most common genetic defect associated with deep vein thrombosis (DVT) is a mutation in the Factor V gene (G1691A), known as Factor V Leiden (FVL). We investigated the genotypes for FVL in 571 individuals in Venezuela: 208 patients with DVT, 175 patients with acute myocardial infarction, 54 patients with stroke, and 134 control subjects. Our results showed in the population analyzed here that the FVL was associated with a fourfold increase in the risk for DVT (odds ratio, 4.24; 95% confidence interval, 1.35-14.79); particularly, women carriers showed a 6.5-fold increase in the risk for DVT. No relation was observed between the presence of FVL and the risk for acute myocardial infarction or stroke. In conclusion, a clear association between the FVL mutation and DVT was observed in the population analyzed in Venezuela. These results are in agreement with those found in other populations with different ethnic backgrounds.

Activated protein C resistance in patients with arterial ischemic stroke

BACKGROUND

Activated C protein resistance (APC-R) has recently been reported to be a common cause of thrombophilia; it may be acquired or caused by a genetic defect (factor V Leiden mutation). It is clear that there is an association between APC-R and venous thrombosis. It has been suggested that there is a possible relationship of APC-R with arterial ischemic stroke (IS), but case-control studies have not given enough clues for considering APC-R as a main risk factor.

OBJECTIVES

To assess the incidence of APC-R in patients with IS of several ethiologies in Buenos Aires.

PATIENTS AND METHODS

Seventy-two patients with IS were assessed for signs or symptoms of previous clinical thrombophilia and the presence of vascular risk factors (RF). They were searched for APC-R (COATEST, APC resistance-V, with a predilution of the samples) test. Determinations were carried out between 1 to 4 months after the ischemic episode. The plasma of 50 healthy control subjects (blood donors) was used as controls.

RESULTS

None of the patients had signs of previous thrombophilia; 57 (79.2%) had RF for IS, and 3 (4.2%) had APC-R (all of them with RF). One subject in the control group (2%) showed a low APC response (1/50). The occurrence of APC-R among patients with stroke was not significantly higher when compared with the occurrence of APC-R among the control subjects.

CONCLUSIONS

In the present series, the incidence of factor V Leiden related APC-R in the group with IS was similar to the healthy population. Other risk factors were associated in patients showing APC-R.

Factor V Leiden and prothrombin gene G20210A mutation in children with cerebral thromboembolism

We investigated whether there is an association between factor V Leiden (FVL) and/or prothrombin gene G20210A mutation (PT20210A) and cerebral thromboembolism in a pediatric Argentinean population. From May 1992 to January 2002, 44 consecutive children with arterial ischemic stroke (AIS) and 23 children with cerebral sinovenous thrombosis (SVT) were prospectively studied at a single center. The prevalence of both mutations was compared with a 102 age-matched controls. In children with AIS, the frequencies (patients vs. controls), odds ratio (OR), and 95% confidence interval (95% CI) for the presence of FVL were as follows: 2.3% vs. 2%, OR/95% CI, 1.16/0.2 to 13.2; P value = 0.99. No cases of PT20210A were found in this group. In children with SVT, the frequencies (patients vs. controls), OR, and 95% CI were as follows: FVL (4.3% vs. 2%, OR/95% CI, 2.27/0.22 to 6.2; P value = 0.99) and PT20210A (4.3% vs. 1%; OR/95% CI, 4.6/0.3 to 76.3; P value = 0.3354). One child with PT20210A also had an inherited protein C deficiency. In 12 (18%) out of the 67 children with cerebral thromboembolism, without the aforementioned mutations, other prothrombotic disorders were detected. Although a multi-center prospective study with a large number of Argentinean pediatric patients is needed to obtain considerable evidence, no association between factor V Leiden and/or prothrombin gene G20210A mutation and cerebral thromboembolism was found in this pediatric series.