Familial early onset Parkinson's disease caused by a homozygous frameshift variant in PARK7: Clinical features and literature update.

Background: Bi-allelic mutations in PARK7 are a rare cause of autosomal recessive early onset Parkinson's disease (EO-PD). To date, 30 individuals harbouring 20 unique causative variants have been described. Understanding of the spectrum of clinical features and natural history of PARK7 mediated EO-PD remain limited.