Familial IBGC caused by SLC20A2 mutation presenting as paroxysmal kinesigenic dyskinesia

Familial idiopathic basal ganglia calcification (IBGC) is a rare autosomal dominant inherited disorder with metabolic dysfunction of calcium and phosphorus [ [1] Hsu S.C. Sears R.L. Lemos R.R. Quintáns B. Huang A. Spiteri E. et al. Mutations in SLC20A2 are a major cause of familial idiopathic basal ganglia calcification. Neurogenetics. 2013; 14: 11-22 Crossref PubMed Scopus (119) Google Scholar ]. Defects of solute carrier family 20 phosphate transporter member 2 (SLC20A2) gene have been considered to be the major cause of familial IBCG [ 1 Hsu S.C. Sears R.L. Lemos R.R. Quintáns B. Huang A. Spiteri E. et al. Mutations in SLC20A2 are a major cause of familial idiopathic basal ganglia calcification. Neurogenetics. 2013; 14: 11-22 Crossref PubMed Scopus (119) Google Scholar , 2 Nicolas G. Pottier C. Charbonnier C. Guyant-Maréchal L. Le Ber I. Pariente J. et al. Phenotypic spectrum of probable and genetically-confirmed idiopathic basal ganglia calcification. Brain. 2013; 136: 3395-3407 Crossref PubMed Scopus (155) Google Scholar ]. Recent evidence suggests that sporadic IBGC might be associated with paroxysmal kinesigenic dyskinesia (PKD) [ [3] Chung E.J. Cho G.N. Kim S.J. A case of paroxysmal kinesigenic dyskinesia in idiopathic bilateral striopallidodentate calcinosis. Seizure. 2012; 21: 802-804 Abstract Full Text Full Text PDF PubMed Scopus (16) Google Scholar ]. However, the etiology and pathophysiology of such a relationship have not been elucidated. We describe an IBGC family, in which all patients presented with juvenile-onset PKD, caused by a novel deletion mutation in the SLC20A2 gene.