This is also the case for prolidase D (PEPD) deficiency (95), which has been associated with the development of systemic lupus erythematosus (SLE) (96), and zeta chain of T cell receptor-associated protein kinase 70 (ZAP-70) (97) and nuclear factor of activated T cells 5 (NFAT5) deficiencies (98). Here, ZAP70 is linked to systemic lupus erythematosus.