In some patients, instead of the signs typically observed in MG (such as lytic bone lesions, hypercalcemia, anemia, and renal insufficiency), the most revealing symptoms are those of a dysfunctional endocrine system, thus confounding the diagnosis of MG—an especially likely situation when the presence of monoclonal protein (M-protein) is very weak and the serum protein electrophoresis (sPEP) profile appears normal. The gene discussed is MYOM2; the disease is hypercalcemia disease.