Gain-of-function (GOF) mutations in <i>STIM1</i> are responsible for tubular aggregate myopathy and Stormorken syndrome (TAM/STRMK), a clinically overlapping multisystemic disease characterised by muscle weakness, miosis, thrombocytopaenia, hyposplenism, ichthyosis, dyslexia, and short stature. The gene discussed is STIM1; the disease is transient myeloproliferative syndrome.