IFNG and glycogen storage disease VI: EBNA: Epstein-Barr nuclear virus antigen 1; EIA: enzyme-linked immunosorbent assay; IGRA: interferon gamma release assay; CSF: cerebrospinal fluid; PCR: polymerase chain reaction; AU: arbitrary units; VCA: viral capsid antigen; VDRL: Venereal Disease Research Laboratory; HIV: human immunodeficiency virus