Pathophysiology of Primary Familial Brain Calcification

Primary familial brain calcification (PFBC) is a dominantly or recessively inherited neurodegenerative disease characterized by bilateral basal ganglia calcifications. Patients affected by PFBC present with diverse motor and nonmotor symptoms. Mutations in seven genes (SLC20A2, XPR1, PDGFB, PDGFRB, MYORG, NAA60, and JAM2) are associated with PFBC. PFBC genes encode proteins that comprise inorganic phosphate transporters, growth factor and its receptor, a cell adhesion molecule, and enzymes. It remains to be determined whether these proteins interact within a single disrupted pathway or whether mutations affect distinct pathways in the same cell type. Although vessel calcification is a diagnostic criterion of PFBC, its causal role in neurodegeneration needs to be established. This review provides an overview of PFBC genes, including animal models that have yielded insights into the underlying pathophysiologic mechanisms, such as the role of specific cell types in the progression of vascular calcification.