EFCAB13 and myalgic encephalomeyelitis/chronic fatigue syndrome: However, only two SNPs: rs4968318, a missense variant of EFCAB13 (MAFME/CFS = 42.7%, MAFHC = 39.1%, p = 0.03) and rs1260333, an intronic variant distal to GCKR (MAFME/CFS = 46.2%, MAFHC = 42.8%, p = 0.04) were significant at the unadjusted threshold of p < 0.05.