Though a notable rarity, isolated neurosarcoidosis should also be considered in cases of aseptic meningitis non responsive to antibiotic and antiviral treatment; ACE should not be considered as an absolute marker of sarcoidosis, with other markers such as IL-2R, β2-microglobulin, and neopterin in CSF being helpful in these cases. The gene discussed is HLA-G; the disease is aseptic meningitis.