Primary familial brain calcifications.

Primary familial brain calcification (PFBC) is a neurodegenerative disease with characteristic calcium deposits in the basal ganglia and other brain regions. The disease usually presents as a combination of abnormal movements, cognitive and psychiatric manifestations, clinically indistinguishable from other adult-onset neurodegenerative disorders. The differential diagnosis must be established with genetic and nongenetic disorders that can also lead to calcium deposits in encephalic structures. In the past years PFBC causal mutations have been discovered in genes related to calcium phosphate homeostasis (SLC20A2, XPR1) and in genes involved with endothelial function and integrity (PDGFB, PDGFRB). The most frequently mutated gene is SLC20A2, where mutations can affect any domain of the protein. There is no clearcut relationship between the specific mutation/gene, onset age, neuroimaging pattern, and severity of clinical manifestations. The discovery of the genetic basis of PFBC provides not only a diagnostic tool, but also an insight into the pathomechanisms and potential therapeutic trials for this rare disease.