P2RX1 and fragile X-associated tremor/ataxia syndrome: Of the 716 proteins associated with calcium ion binding [GO:0005509 GO_Calcium_Ion_Binding] and calcium-associated proteins associated with FXTAS [TPCN1, TPCN2, ORAI1, ORAI2, ORAI3, CACNA1D, CACNA1F, CACNA1A, CACNA1B, CACNA1E, CACNA1G, CACNA1H, CACNA1I, and P2RX1-7] (Rovozzo et al., 2016), 262 (37%) were identified by MS in FXTAS cortexes.