Besides rare mutations in the P2X7 receptor gene found in familial MS (Sadovnick et al., 2017; Zrzavy et al., 2019), patients with mutations of Arg307Gln (rs28360457), which cause a substantial loss in membrane pore formation, are up to twice less frequent in MS patients, indicating a protective effect of this mutation (Gu et al., 2015). The gene discussed is P2RX7; the disease is myeloid sarcoma.