To date, mutations in 11 IUIS genes (BTK, CD40LG, DOCK8, MAGT1, NFKB1, PRKDC, RAG1, RMRP, STAT1, STK4, and WAS) have been reported in PML patients, most frequently for DOCK8 (3 cases) (28, 31) and STAT1 (4 cases) (26, 32). This evidence concerns the gene DOCK8 and progressive multifocal leukoencephalopathy.