A decrease in myocardial uptake of iodine-123-labeled metaiodobenzylguanidine (123I-MIBG) has been reported in idiopathic Parkinson's disease (PD) using 123I-MIBG myocardial scintigraphy. However, the patient with autosomal recessive juvenile parkinsonism (AR-JP), caused by the parkin gene, presented here showed normal 123I-MIBG myocardial uptake, suggesting that AR-JP is a distinct disease entity from PD. Although the clinical features of AR-JP are sometimes quite similar to those of late-onset idiopathic PD, 123I-MIBG myocardial scintigraphy may be a powerful tool to differentiate PD from other parkinsonian syndromes, including AR-JP. Copyright 2005 Movement Disorder Society.