Abstract-Lower levels of factor VIII and von Willebrand factor (vWF) have been reported in individuals with blood type O compared with individuals with other ABO blood types. However, this relationship has been demonstrated only by association studies and not by linkage studies. Also, it is not clear whether the ABO locus exerts a functional effect directly on these plasma factors or whether the ABO locus is in linkage disequilibrium with another locus that controls these factors. To distinguish between these 2 possibilities, we applied new statistical methods combining linkage and association tests in a pedigree-based sample. In contrast to most previous studies that used the ABO phenotypes, our study used the ABO genotypes, permitting us to distinguish AO from AA and BO from BB. Our results clearly showed significant linkage between the ABO locus and vWF antigen (Pϭ0.00075). In addition, factor VIII coagulant activity and activated partial thromboplastin time showed suggestive linkage with the ABO locus (Pϭ0.10 and Pϭ0.13). All 3 plasma phenotypes showed significant differences between OO and non-OO genotypes. In addition, vWF antigen exhibited significant differences between O heterozygotes and non-OO homozygotes. This study is unique because it used a combined linkage and association test, which indicated that the ABO locus itself has a functional effect on these plasma phenotypes. (Arterioscler Thromb Vasc

In our geographic area, almost 70% of donors who are anti-HCV positive by ELISA are confirmed to be positive by RIBA-2; most of these donors appear to be chronic carriers of HCV and have substantial liver disease.

Mitochondrial neurogastrointestinal encephalomyopathy (MNGIE) is caused by thymidine phosphorylase (TP) deficiency, which leads to toxic accumulations of thymidine (dThd) and deoxyuridine (dUrd). In this work, we report that infusion of platelets from healthy donors to patients with MNGIE restored transiently circulating TP and reduced plasma dThd and dUrd levels, suggesting that treatments to achieve permanent restoration of circulating TP such as allogeneic stem cell transplantation or gene transfer might be therapeutic.