In this narrative review, we synthesized data on primary familial brain calcification (PFBC) and secondary Fahr syndromes, highlight proposed mechanisms linking disturbances in calcium-phosphate-parathyroid hormone (PTH) homeostasis to intracranial parenchymal calcification, and summarize the clinical spectrum from incidental findings to disabling movement, cognitive, and psychiatric manifestations. This evidence concerns the gene PTH and bilateral striopallidodentate calcinosis.