First report of a de novo mutation at SLC20A2 in a patient with brain calcification

Abstract

Primary familial brain calcification (PFBC) is identified by mineralization of the basal ganglia and other brain regions in the absence of known causes. The condition is often inherited in an autosomal dominant pattern and can manifest itself clinically with neuropsychiatric symptoms such as Parkinsonism, headaches, psychosis, and mood swings. Mutations in the SLC20A2 gene account for ~40% of inherited cases, and this gene encodes an inorganic phosphate transporter (PiT-2), a transmembrane protein associated with Pi homeostasis. The p.Y386X mutation in SLC20A2 was identified in a patient who presented migraines, brain calcification, and mild but chronic hypovitaminosis D. SLC20A2 c.1158C > G single-nucleotide heterozygous mutation results in a premature stop codon and a putative truncated protein of 385 amino acids. Proband parents do not present the mutation, which is also not present in major public SNP databases, suggesting a de novo sporadic trait. This study describes for the first time a de novo SLC20A2 mutation in a PFBC patient with migraine and mild hypovitaminosis D. This data further reinforces the pathogenic role of SLC20A2 mutations as causal factors in PFBC physiopathology.