RYR1 and transient myeloproliferative syndrome: TAM is a relatively rare disorder typically caused by gain-of-function mutations in both STIM1 and ORAI1 [34,35,36,37,38,39,40,41], and to a lesser degree, mutations in genes encoding for CASQ1 and the type-1 ryanodine receptor (RYR1) [34,42,43].