Mutations may also occur in genes that encode various proteins involved in the innate immune response to fungi—notably, the following: PTPN22 (protein tyrosine phosphatase, non-receptor type 22 [also called LYP, or lymphoid tyrosine phosphatase], which is involved in T-cell-receptor signalling) Dectin-1 (an innate pattern recognition receptor essential for the control of fungal infections) CARD9 (caspase recruitment domain-containing protein 9, which is an adaptor molecule important in the production of interleukin (IL) - 17 and for protection against fungal invasion) Patients (dominant and recessive) have cutaneous anergy to Candida, absent proliferative responses to Candida antigen (but normal proliferative responses to mitogens), and intact antibody response to Candida and other antigens.