SLC20A2 and bilateral striopallidodentate calcinosis: Primary familial brain calcification (PFBC) is a rare microvascular calcifying disorder presenting with neuropsychiatric symptoms, which is caused by haploinsufficiency of an inorganic phosphate transporter, SLC20A2. Recently, a deletion encompassing an enhancer region upstream of SLC20A2 was identified in three patients with PFBC [69], and resulted in decreased SLC20A2 expression and phosphate uptake to a similar level as observed in SLC20A2 haploinsufficiency.