Primary Thrombophilia Research Articles

Primary thrombophilia in Mexico. II. Factor V G1691A (Leiden), prothrombin G20210A, and methylenetetrahydrofolate reductase C677T polymorphism in thrombophilic Mexican mestizos

We have shown that in Mexican mestizo patients with clinical features of primary thrombophilia, 39% have activated protein C resistance phenotype, 5% protein C deficiency, and 2% protein S deficiency. In the present study, in a group of 37 thrombophilic Mexicans and 50 normal controls, we assessed the factor V G1691A (Leiden), the prothrombin G20210A, and the methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphisms. Four patients were found to be heterozygous for factor V Leiden, 5 heterozygous for the prothrombin 20210, 16 heterozygous, and 6 homozygous for the MTHFR 677. There were four individuals with co-segregation of alleles: two heterozygotes for the factor V Leiden/prothrombin 20210, one heterozygote for prothrombin 20210/MTHFR 677, and one heterozygote for prothrombin 20210/homozygote for MTHFR 677. For factor V Leiden, prothrombin 20210, and MTHFR 677 mutations, the allele frequencies were respectively 1% (±0.2%, α = 0.05), <1% and 51% (±5%, α = 0.05), with calculated relative risks for thrombosis of 5.94 (P = 0.08), >7.66 (P < 0.05), and 0.44 (P NS), respectively. In Mexican mestizo thrombophilic patients, the low prevalence of the factor V Leiden mutation (10.8%) and the high prevalence of the prothrombin 20210 mutation (13.5%) contrast with those identified in Caucasian thrombophilic patients (21% and 6%, respectively; P < 0.01). On the other hand, the high prevalence of the MTHFR 677 mutation gene both in normal controls (78%) and thrombophilic patients (61%) does not support a role of this mutation in the thrombogenesis of Mexican mestizo patients. Am. J. Hematol. 66:28–31, 2001. © 2001 Wiley-Liss, Inc.

Primary thrombophilia in Mexico. II. Factor V G1691A (Leiden), prothrombin G20210A, and methylenetetrahydrofolate reductase C677T polymorphism in thrombophilic Mexican mestizos.

We have shown that in Mexican mestizo patients with clinical features of primary thrombophilia, 39% have activated protein C resistance phenotype, 5% protein C deficiency, and 2% protein S deficiency. In the present study, in a group of 37 thrombophilic Mexicans and 50 normal controls, we assessed the factor V G1691A (Leiden), the prothrombin G20210A, and the methylenetetrahydrofolate reductase (MTHFR) C677T gene polymorphisms. Four patients were found to be heterozygous for factor V Leiden, 5 heterozygous for the prothrombin 20210, 16 heterozygous, and 6 homozygous for the MTHFR 677. There were four individuals with co-segregation of alleles: two heterozygotes for the factor V Leiden/prothrombin 20210, one heterozygote for prothrombin 20210/MTHFR 677, and one heterozygote for prothrombin 20210/homozygote for MTHFR 677. For factor V Leiden, prothrombin 20210, and MTHFR 677 mutations, the allele frequencies were respectively 1% (+/-0.2%, alpha = 0.05), <1% and 51% (+/-5%, alpha = 0.05), with calculated relative risks for thrombosis of 5.94 (P = 0.08), >7.66 (P < 0.05), and 0.44 (P NS), respectively. In Mexican mestizo thrombophilic patients, the low prevalence of the factor V Leiden mutation (10.8%) and the high prevalence of the prothrombin 20210 mutation (13.5%) contrast with those identified in Caucasian thrombophilic patients (21% and 6%, respectively; P < 0.01). On the other hand, the high prevalence of the MTHFR 677 mutation gene both in normal controls (78%) and thrombophilic patients (61%) does not support a role of this mutation in the thrombogenesis of Mexican mestizo patients.

Primary thrombophilia in Mexico: a prospective study.

A group of 102 Mexican Mestizo patients with appropriate clinical features suggestive of primary thrombophilia was prospectively studied. Thirty-nine percent of them had activated protein C resistance, but only four patients displayed the factor V Leiden mutation. Five percent of the individuals were found to be protein C deficient, whereas 2% had protein S deficiency. No cases of abnormalities in antithrombin III, plasminogen, tissue-type plasminogen activator or plasminogen activator inhibitor were found. The low prevalence of the activated protein C resistance genotype, probably stemming from the genetic admixture of the Mexican Mestizo group is noteworthy.

Primary thrombophilia in Mexico: A prospective study

Primary thrombophilia in Mexico: A prospective study

Thrombophilia, hypofibrinolysis, and alveolar osteonecrosis of the jaws

Objectives Our specific aim in 49 patients (42 women, 7 men) with osteonecrosis of the jaw was to determine whether thrombophilia (increased tendency to intravascular thrombosis) or hypofibrinolysis (reduced ability to lyse thrombi) were associated with this regional avascular necrosis. Study designs Determinants of thrombosis and fibrinolysis were compared in healthy controls and in 42 women and 7 men who had biopsy-proven idiopathic osteoncrosis of the jaw with severe chronic jaw or facial pain syndromes and failure to respond to conventional medical and dental treatments. Results Of the 49 patients, 35 (71%) had thrombophilia or hypofibrinolysis and only 14 were normal. Thrombophilia as a sole coagulation defect was found in 10 patients, 7 with resistance to activated protein C and 3 with low protein C (deficiency of an antithrombotic protein). Hypofibrinolysis with low stimulated tissue plasminogen activator activity and high lipoprotein (a) (an atherogenic, hypofibrinolytic lipoprotein) were found as sole coagulation defects in seven and eight patients, respectively. Ten patients had mixed defects; 7 of these 10 had thrombophilia with resistance to activated protein C. Sinusoidal dilatation was a constant feature in maxillary and mandibular bone biopsies, suggesting venous occlusion with intramedullary hypertension. Marrow fibrosis and occasional fibrin plugs were additional microscopic features believed to impair venous drainage and to contribute to ischemic necrosis of the alveolar bone. Conclusions Primary thrombophilia and hypofibrinolysis appear to be common, heritable, pathophysiologic risk factors for idiopathic osteonecrosis of the jaws. These coagulation defects may also contribute to alveolar neuralgia, atypical odontalgia and facial neuralgia, idiopathic trigeminal neuralgia, and to treatment failures so often encountered in patients with alveolar osteonecrosis and disabling chronic facial and jawbone pain syndromes.