A Japanese family with idiopathic basal ganglia calcification carrying a novel XPR1 variant.

•A novel pathogenic XPR1 variant found in a Japanese IBGC family.•The proband exhibited neurological signs and brain calcification.•The asymptomatic mother also showed brain calcification.•IBGC with XPR1 variant can be asymptomatic despite remarkable brain calcification.•Assessments of asymptomatic carriers can help understand radiological and clinical penetrance.