Our results confirm the STIM1 L96V-associated Ca2+ homeostasis dysfunction on patient-derived cells and demonstrate, for the first time, that the STIM1 L96V mutation alters the myogenic differentiation program, particularly regarding the terminal differentiation step, thereby providing new insights in the pathogenesis of STIM1-related TAM. This evidence concerns the gene STIM1 and transient myeloproliferative syndrome.