Thrombin-activable fibrinolysis inhibitor (TAFI) is a recently described carboxypeptidase that is potentially involved in the regulation of fibrinolysis by decreasing plasminogen binding to the fibrin surface. This role makes the TAFI gene a good candidate in atherothrombotic diseases. The great interindividual variability of plasma TAFI antigen levels is poorly explained by lifestyle characteristics, thus suggesting its genetic determination. To test this hypothesis, the promoter and the 3-untranslated region of the TAFI gene were screened for polymorphisms, and their contribution to the variability of plasma TAFI antigen levels was evaluated. Seven new polymorphisms are described, 5 in the promoter (C-2599G, ؊2345 2G/1G, A-1690G, G-1102T, and G-438A) and 2 in the 3UTR (C؉1542G and T؉1583A). All these polymorphisms were in strong linkage disequilibrium with each other and with the previously described Ala147Thr polymorphism. They generated 4 main haplotypes, accounting for 80% of all observed haplotypes. In univariate analyses, all polymorphisms were associated with plasma TAFI Ag levels and, individually, contributed to a large fraction of plasma TAFI Ag levels, ranging from 20% to 52%. In a stepwise regression analysis including all polymorphisms, several combinations remained significantly and independently associated with plasma TAFI Ag levels: C؉1542G associated with Ala147Thr, T؉1583A, or ؊2345 2G/1G explaining 61.6%, 60.2%, and 58.1% of the variance, respectively. These findings clearly demonstrate that circulating levels of TAFI are strongly determined by polymorphic variations in the promoter and the 3UTR of the TAFI gene. (Blood. 2001;97:2053-2058

Abstract-The thrombin-activatable fibrinolysis inhibitor (TAFI) is a recently described inhibitor of fibrinolysis that decreases plasminogen binding to the fibrin surface. The plasma TAFI concentration is almost entirely genetically determined. We investigated whether plasma TAFI levels and polymorphisms located in the TAFI gene could constitute risk markers of myocardial infarction (MI). Plasma TAFI antigen (Ag) levels were assayed by ELISA and 2 TAFI gene polymorphisms (Ala147Thr and Cϩ1542G in the 3Ј untranslated region) were determined in a large European case-control study. This study compared 598 men recruited 3 to 6 months after MI with 653 age-matched controls from North Europe (Stockholm, Sweden, and London, England) and South Europe (Marseilles, France, and San Giovanni Rotondo, Italy). A TAFI Ag value above the 90th percentile was associated with a significantly lower risk of MI (odds ratio 0.55, PϽ0.02), indicating that elevated TAFI may be protective against MI. As previously shown, the 2 TAFI gene polymorphisms were in strong linkage disequilibrium and were associated with the TAFI Ag concentration, with carriers of the Thr147 and 1542C alleles having higher levels (PϽ0.0005). These effects were similar in controls and cases and in each center. There was a difference in allele frequency between cases and controls for the Ala147Thr polymorphism, with Thr147 allele carriers being more frequent in controls than in cases in 2 centers, Stockholm (Pϭ0.03) and San Giovanni Rotondo (Pϭ0.03); the odds ratio for the entire cohort was 0.78 (PϽ0.05). In conclusion, patients with a recent MI presented lower values of TAFI Ag and higher frequencies of the "TAFI-decreasing" alleles. The geographical differences observed do not contribute to explaining the North-South gradient in MI risk in Europe. Key Words: thrombin-activatable fibrinolysis inhibitors Ⅲ myocardial infarction Ⅲ genetic polymorphisms Ⅲ fibrinolysis T he thrombin-activatable fibrinolysis inhibitor (TAFI), also known as procarboxypeptidase B and procarboxypeptidase U, has been recently described. 1-3 It can potently inhibit fibrinolysis by removing carboxy-terminal lysine residues from partially degraded fibrin, decreasing plasminogen binding on its surface. 4 -7 Because of its role in the fibrinolytic system, TAFI may be implicated in atherothrombotic diseases. Studies conducted in different animal models support a physiological role of TAFI in the regulation of fibrinolysis. 8 -11 In humans, van Tilburg et al, 12 have shown that an increased plasma TAFI antigen (Ag) concentration could be a risk marker for venous thrombosis. 12 In a pilot study of men with stable angina pectoris and angiographically verified coronary artery disease, it was found that the plasma levels of TAFI were significantly higher in the patients than in healthy population-based age-matched men. 13 The between-individual differences in plasma TAFI concentration are only partly explained by environmental factors, suggesting a strong influence of genetic factors. 14,15 The hum...

Common birthmarks can be an indicator of underlying genetic disease but are often overlooked. Mongolian blue spots (dermal melanocytosis) are usually localized and transient, but they can be extensive, permanent, and associated with extracutaneous abnormalities. Co-occurrence with vascular birthmarks defines a subtype of phakomatosis pigmentovascularis, a group of syndromes associated with neurovascular, ophthalmological, overgrowth, and malignant complications. Here, we discover that extensive dermal melanocytosis and phakomatosis pigmentovascularis are associated with activating mutations in GNA11 and GNAQ, genes that encode Gα subunits of heterotrimeric G proteins. The mutations were detected at very low levels in affected tissues but were undetectable in the blood, indicating that these conditions are postzygotic mosaic disorders. In vitro expression of mutant GNA11R183C and GNA11Q209L in human cell lines demonstrated activation of the downstream p38 MAPK signaling pathway and the p38, JNK, and ERK pathways, respectively. Transgenic mosaic zebrafish models expressing mutant GNA11R183C under promoter mitfa developed extensive dermal melanocytosis recapitulating the human phenotype. Phakomatosis pigmentovascularis and extensive dermal melanocytosis are therefore diagnoses in the group of mosaic heterotrimeric G-protein disorders, joining McCune-Albright and Sturge-Weber syndromes. These findings will allow accurate clinical and molecular diagnosis of this subset of common birthmarks, thereby identifying infants at risk for serious complications, and provide novel therapeutic opportunities.

The TOPICOP score can be feasibly applied across countries and may therefore be useful for obtaining qualitative and quantitative data from international studies and for adapting patient education and treatment.