A heterozygous deletion of PDGFB gene causes paroxysmal kinesigenic dyskinesia with primary familial brain calcification

Primary familial brain calcification (PFBC) is a neurodegenerative disease characterized with calcium deposition in multiple brain regions. Mutations in PDGFB have been discovered in sporadic and familial PFBC cases. While several known variants displayed loss-of function, no complete deletion of platelet-derived growth factor B (PDGFB) has been reported. For the diagnostic purpose, brain computerized tomography or magnetic resonance imaging scanning and whole-genome sequencing were performed on the proband and family members in the pedigree. We identified a heterozygous PDGFB complete deletion in a Chinese pedigree. The proband presented with paroxysmal kinesigenic dyskinesia (PKD), a rare symptom in PFBC. The proband's mother carrying the same mutation was asymptomatic. For the first time, we reported a PFBC with a heterozygous deletion of PDGFB, and provided evidence of haploinsufficiency in the pathogenesis of PFBC.