•Severe dehydration including orthostatic changes•Renal dysfunction•Neurological dysfunction•Metabolic acidosis•Abnormal electrolyte levels, including hyponatremia, hypokalemia, hypocalcemia, or hypomagnesemia•Hypoproteinemia (albumin level <3 g/dL)•Weight loss, >4.5 kg. The gene discussed is ALB; the disease is familial primary hypomagnesemia.