Novel SLC20A2 mutations identified in southern Chinese patients with idiopathic basal ganglia calcification

Abstract

Idiopathic basal ganglia calcification (IBGC) is a rare neuropsychiatric disorder characterized by bilateral and symmetric cerebral calcifications. Recently, SLC20A2 was identified as a causative gene for familial IBGC, and three mutations were reported in a northern Chinese population. Here, we aimed to explore the mutation spectrum of SLC20A2 in a southern Chinese population. Sanger sequencing was employed to screen mutations within SLC20A2 in two IBGC families and 14 sporadic IBGC cases from a southern Han Chinese population. Four novel mutations (c.82G>A p.D28N, c.185T>C p.L62P, c.1470_1478delGCAGGTCCT p.Q491_L493del and c.935-1G>A) were identified in two families and two sporadic cases, respectively; none were detected in 200 unrelated controls. No mutation was found in the remaining 12 patients. Different mutations may result in varied phenotypes, including brain calcification and clinical manifestations. Our study supports the hypothesis that SLC20A2 is a causative gene of IBGC and expands the mutation spectrum of SLC20A2, which facilitates the understanding of the genotype-phenotype correlation of IBGC.

Keywords: CT; Computed tomography; FD; FIBGC; Fahr disease; Familial Idiopathic basal ganglia calcification; Genetic heterogeneity; IBGC; Idiopathic basal ganglia calcification; Novel mutation; PCR; PTH; Parathyroid hormone; PiT2; Polymerase chain reaction; SLC20A2; Type III sodium-dependent phosphate transporter 2.