Atypical parkinsonism on Guadeloupe, comparison with the parkinsonism-dementia complex of Guam, and environmental toxic hypotheses.

INTRODUCTION: : On Guadeloupe, atypical parkinsonism is abnormally frequent, and represents 75% of progressive parkinsonism while Parkinson's disease (PD) accounts for only 25%, which is an inversed percentage in comparison with Europe. Herbal tea made with Annonaceae leaves (containing benzyltetrahydroisoquinolines (Be-TIQ), tetrahydroprotoberberines (THPB) and acetogenins (potent mitochondrial complex I inhibitors) are commonly used on Guadeloupe. CLINICAL STUDY: : Of 265 patients studied on Guadeloupe, 66 (25%) had PD, and 199 (75%) had atypical parkinsonism. This latter group includes 58 patients (29%) with progressive supranuclear palsy (PSP), and 100 patients (50%) with unclassifiable parkinsonism (UP). This focus resembles the parkinsonism-dementia complex (PDC) described on Guam, where a very high prevalence of atypical parkinsonism has been reported since the second World War, including one-third of PSP. A preliminary case-control study on Guadeloupe showed a significant higher consumption of fruits and herbal tea of Annonaceae in atypical parkinsonian cases (PSP and unclassifiable parkinsonism, UP), compared to hospital controls and to idiopathic PD. DISCUSSION: : The overrepresentation of atypical parkinsonism on Guadeloupe and Guam could be related to the consumption of plants containing (simultaneously) isoquinoline derivates which are toxic for dopaminergic neurons and inhibitors of the mitochondrial respiratory chain such as acetogenins. This hypothesis is in keeping with epidemiologic data and experimental studies showing neuronal loss after exposure to isoquinolines or acetogenins.