Objective: Challenging differential diagnosis Background: Basal ganglia calcification (BGC) is a rare sporadic or hereditary central nervous system (CNS) abnormality, characterized by symmetric or asymmetric calcification of the basal ganglia. Case Report: We report the case of a 65-year-old Gypsy female who was admitted for a tetanic seizure, and who had a history of polyneuropathy, restless-leg syndrome, retinopathy, diabetes, hyperlipidemia, osteoporosis with consecutive hyperkyphosis, cervicalgia, lumbalgia, struma nodosa requiring thyroidectomy and consecutive hypothyroidism, adipositas, resection of a vocal chord polyp, arterial hypertension, coronary heart disease, atheromatosis of the aorta, peripheral artery disease, chronic obstructive pulmonary disease, steatosis hepatis, mild renal insufficiency, long-term hypocalcemia, hyperphosphatemia, impingement syndrome, spondylarthrosis of the lumbar spine, and hysterectomy. History and clinical presentation suggested a mitochondrial defect which also manifested as hypoparathyroidism or Fanconi syndrome resulting in BGC. After substitution of calcium, no further tetanic seizures occurred. Conclusions: Patients with BGC should be investigated for a mitochondrial disorder. A mitochondrial disorder may also manifest as tetanic seizure.