Several clinical consequences arise: First, there is the susceptibility to develop other small-bowel diseases such as inflammatory bowel disease or parasite infections (Giardiasis for example, which can histologically mimic CD), then there is the issue regarding diagnosis of CD in these patients, as IgA-based serology can lead to false-negative results (for this reason testing for suspicion of CD includes total serum IgA dosing or both IgA and IgG-based serology), and last, there is a risk of serious transfusion reactions in patients with anti-IgA antibodies [68,69]. Here, CD79A is linked to Cowden disease.