Directed search for thrombomodulin gene mutations

Association of Thrombomodulin Gene Polymorphism (C1418T) With Coronary Artery Disease in Pakistani Population

Objectives

To find out the association between Thrombomodulin gene polymorphism (C1418T) with coronary artery disease in population of Karachi, Pakistan.

Methods

This case-control study was conducted in Tabba Heart Institute in collaboration with the National Institute of Blood Diseases, Karachi. We compared C/T dimorphism in 92 cases with 90 control subjects by allele-specific amplification. The results of PCR were confirmed by Gene sequencing. All the laboratory methods were strictly in compliance with the international standards. All variables that were either statistically significant in the univariate analyses or potentially important with respect to prevention or biologically relevant variables were included in logistic-regression analyses. Potential confounding was assessed with the use of multivariate models adjusted for participant's characteristics and other major risk factors for coronary artery disease. All reported p values are two-tailed, with statistical significance at p value < 0.05.

Results

The frequency of CC, C/T and TT genotype was 81 (90%), 6 (6.7%) 3 (3.3%) in controls and 67 (72.8%), 20 (21.7%) and 5 (5.4%) in cases respectively. In cases group the CT/TT genotypes were found to be significantly highly represented among the patients with coronary artery diseases when compared with control group (p-value 0.009).

Conclusion

TM C1418T polymorphism emerges as a risk marker in Coronary Artery Disease patients in the population of Karachi, Pakistan.

Thrombomodulin Ala455Val Polymorphism and the risk of cerebral infarction in a biracial population: the Stroke Prevention in Young Women Study

Background

The genes encoding proteins in the thrombomodulin-protein C pathway are promising candidate genes for stroke susceptibility because of their importance in thrombosis regulation and inflammatory response. Several published studies have shown that the Ala455Val thrombomodulin polymorphism is associated with ischemic heart disease, but none has examined the association with stroke. Using data from the Stroke Prevention in Young Women Study, we sought to determine the association between the Ala455Val thrombomodulin polymorphism and the occurrence of ischemic stroke in young women.

Methods

All 59 hospitals in the greater Baltimore-Washington area participated in a population-based case-control study of stroke in young women. We compared 141 cases of first ischemic stroke (44% black) among women 15 to 44 years of age with 210 control subjects (35% black) who were identified by random digit dialing and frequency matched to the cases by age and geographical region of residence. Data on historical risk factors were collected by standardized interview. Genotyping of the thrombomodulin Ala455Val polymorphism was performed by pyrosequencing.

Results

The A allele (frequency = 0.85) was associated with stroke under the recessive model. After adjustment for age, race, cigarette smoking, hypertension, and diabetes, the AA genotype, compared with the AV and VV genotypes combined, was significantly associated with stroke (odds ratio 1.9, 95% CI 1.1–3.3). The AA genotype was more common among black than white control subjects (81% versus 68%) but there was no significant interaction between the risk genotype and race (adjusted odds ratio 2.7 for blacks and 1.6 for whites). A secondary analysis removing all probable (n = 16) and possible (n = 15) cardioembolic strokes demonstrated an increased association (odds ratio 2.2, 95% CI 1.2–4.2).

Conclusions

Among women aged 15 to 44 years, the AA genotype is more prevalent among blacks than whites and is associated with increased risk of early onset ischemic stroke. Removing strokes potentially related to cardioembolic phenomena increased this association. Further studies are needed to determine whether this polymorphism is functionally related to thrombomodulin expression or whether the association is due to population stratification or linkage to a nearby functional polymorphism.