For example, polymorphisms in PTPN22 (Protein tyrosine phosphatase, non-receptor type 22) which are known to be associated with HT and other autoimmune disorders cause altered Ca2+ flux upon BCR ligation and B cell-restricted expression of risk variants is enough to initiate autoimmunity (29, 50–54). The gene discussed is PTPN22; the disease is Autoimmunity.