CD79A and Cowden disease: The most important serological investigations in the diagnosis of CD are IgA class antitransglutaminase antibodies (TTGA) with the highest sensitivity (98%) and specificity estimated at around 90%, and IgA class antiendomysial antibodies (EMA), this test having a lower sensitivity compared to IgA-class TTGA (90% vs. 98%) but showing an almost absolute specificity for CD.