Basal Ganglia Calcifications for Nephrologists: Fahr/Primary Familial Brain Calcification (PFBC) at the Interface of Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD) and Hypoparathyroidism.

Bilateral basal ganglia calcifications are increasingly recognized on neuroimaging, yet their interface with chronic kidney disease-mineral and bone disorder (CKD-MBD) and hypoparathyroidism is rarely addressed from a nephrology perspective. 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. Targeted searches of the literature and relevant guidelines were used to integrate mechanistic, imaging, and clinical studies with the authors' nephrology experience. Evidence suggests that chronic hypocalcemia with relative hyperphosphatemia in hypoparathyroidism and disordered calcium-phosphate-PTH balance in CKD-MBD (typically secondary hyperparathyroidism) may lower the threshold for basal ganglia mineralization. Symptom control and early metabolic correction can improve neurological outcomes even though radiologic calcifications usually persist. Direct data in dialysis and transplant cohorts remain sparse, representing a major research gap. We propose a pragmatic, nephrology-focused approach: confirm the radiologic pattern, obtain a compact mineral panel in all patients, treat reversible metabolic causes before extensive testing, and reserve PFBC genetic panels for compatible phenotypes and family histories. This framework aims to make basal ganglia calcifications a more familiar and actionable finding in kidney practice.