PT = prothrombin time; APTT = activated partial thromboplastin time; VWF = von Willebrand factor; anti-HIV 1/2 = anti-human immunodeficiency virus 1/2; HBsAg = hepatitis B surface antigen; HCV = hepatitis C virus; ANA = antinuclear antibodies; Anti-SSA = anti-Sjögren’s syndrome A antibody; Anti-SSB = anti-Sjögren’s syndrome B antibody; Anti-SM = anti-Smith antibody. The gene discussed is VWF; the disease is Down syndrome.