The prothrombin G20210A mutation: a new high-prevalence congenital risk factor for thrombosis

Endothelial cell protein C receptor gene 6936A/G polymorphism is associated with venous thromboembolism

Venous thromboembolism (VTE) is a common, yet complex disorder. Genetic factors have been suggested to play a role in disease development. We, therefore, conducted a case-control study to examine the potential association of the 6936A/G polymorphism in the endothelial cell protein C receptor (EPCR) gene with the occurrence of venous thromboembolism. We measured the plasma levels of soluble EPCR (sEPCR) in blood samples collected from 112 patients with VTE and 112 age- and gender-matched healthy donors using enzyme-linked immunosorbent assay (ELISA) and amplified the EPCR gene product by PCR. Gene product bands were sequenced to identify EPCR gene polymorphisms. We found that the 6936 AG and GG genotypes were over-represented in the VTE patients. By multivariate analysis, subjects carrying the 6936 G allele were found to have an increased risk of thrombosis (OR=1.784; 95% CI, 1.113-2.891; P<0.05). In conclusion, the EPCR gene 6936A/G polymorphism, which is associated with elevated plasma sEPCR levels, is a potential candidate risk factor for venous thromboembolism.

Crohn's and Behçet's disease association presenting with superior vena cava thrombosis

A 21-year-old male patient with a 6-year history of Crohn's disease presented with shoulder pain and edema in the neck and bilateral supraclavicular fossa. Color Doppler ultrasonography and computed tomography scan revealed bilateral thrombosis of the external jugular veins, brachiocephalic veins, and superior vena cava. Other etiologies were appropriately ruled out and the thrombosis was initially attributed to Crohn's disease. In the follow-up, the patient developed recurrent, painful orogenital ulcers and acne vulgaris-like skin eruptions. HLA tissue typing was HLA B-51. The diagnosis of Crohn's disease associated with Behçet's disease was made. Although there are several case reports describing such an association, a Medline research revealed that this was the first presentation of such an association with thrombosis. Thrombosis in unusual sites may reflect the uncommon association of Crohn's disease with hypercoagulable conditions such as Behçet's disease.

Prevalence of factor V G1691A (Leiden), prothrombin G20210A, and methylene tetrahydrofolate reductase C677T thrombophilic mutations in children with inflammatory bowel disease

BACKGROUND

Patients with inflammatory bowel disease (IBD) have an increased incidence of thromboembolic events. This risk may be caused by an increased frequency of thrombophilic mutations such as factor V Leiden G1691A (FVL), prothrombin G20210A (PT), or methylene tetrahydrofolate reductase C667T (MTHFR). Prevalence rates of heterozygous mutations in FVL, PT, and MTHFR are reported for whites (1.8%, 1.3%, 26.6%, respectively), blacks (0.8%, 0.3%, and 12.4%, respectively), and Hispanics (1.2%, 2.4%, and 41.5%, respectively). We sought to determine the prevalence of these thrombophilic mutations in a large cohort of children with IBD.

METHODS

Children aged 21 years or younger with IBD were genotyped for FVL, PT, and MTHFR mutations by polymerase chain reaction amplification and restriction enzyme digestion. Prevalence rates were compared with established rates in the respective populations.

RESULTS

Of 92 patients enrolled, 89 (62 with Crohn disease, 24 with ulcerative colitis, and 3 with indeterminate colitis) had genotype results available. The mean age was 13.3 +/- 4.2 years (range, 2-21 years). Statistical analysis was performed on 89 FVL, PT, and MTHFR allele pairs. Polymerase chain reaction genotyping identified 5 patients with heterozygous FVL mutations, 3 patients heterozygous for the PT mutation, and 36 patients heterozygous and 4 patients homozygous for the MTHFR mutation. The thrombophilic allele mutation frequencies in our sample were not significantly different from predicted weighted average values: FVL, 2.8% versus 1.5%; PT, 1.7% versus 1.1%; and MTHFR, 24.7% versus 24.4%. In 24 patients with a family history of thrombosis, 1 was heterozygous for FVL and for MTHFR, 1 was heterozygous for FVL and homozygous for MTHFR, 2 were heterozygous for PT, and 9 were heterozygous MTHFR. There was no significant correlation between family history of thrombosis and presence of a thrombophilic mutation. The four patients with homozygous mutations for MTHFR, two of whom also were heterozygous for FVL, did not have either a personal history of thrombosis or a family history of thrombotic events. Two patients had thrombotic events without mutations in these genotypes: one had protein S deficiency and the other had no identifiable cause.

CONCLUSIONS

The presence of genetic mutations that predispose to hypercoagulable states does not appear to correlate with the prevalence of IBD or to thromboembolic events in patients with IBD. There was no statistical difference between the proportions of the mutated allele frequency in our study patients and the general population.

Specialized intestinal metaplasia and carditis at the gastroesophageal junction in Chinese patients undergoing endoscopy

OBJECTIVE

Specialized intestinal metaplasia (SIM) is often found at a normal-looking gastroesophageal junction on routine biopsy. The prevalence of SIM in Asian populations has not been recorded. Its significance is also unclear. The objective of the study was to document the prevalence of SIM at the gastroesophageal junction in a Chinese population undergoing endoscopy.

METHODS

Biopsies were taken at the gastroesophageal junction in 145 patients, both at the squamocolumnar junction and immediately below in the gastric cardia. Specimens were examined for the type of epithelium (squamous, cardiac, and fundic), the presence of SIM, and Helicobacter pylori (H. pylori).

RESULTS

Of 145 patients who underwent endoscopy, 136 had a normal-looking gastroesophageal junction. Cardiac epithelium was found in 100 patients. Of these 100 patients, SIM was documented in 34% of patients and carditis in 20%. Patients with SIM were older compared with those without SIM (mean age 62 yr and 56 yr, p = 0.035). Carditis was more prevalent in patients with SIM. It was present in 11 out of 34 patients who had SIM (32.4%) compared with nine in 66 patients (13.6%) without SIM, p = 0.036. When carditis was found, H. pylori was present at the cardia in 40% of patients (eight of 20) compared with only 18% (14 of 80) in those without carditis, p = 0.039.

CONCLUSIONS

SIM is prevalent at the gastroesophageal junction in Chinese patients undergoing endoscopy and is associated with carditis. Carditis in turn may be related to H. pylori infection.