We characterize the clinical features of Parkinson's syndrome on Guadeloupe and describe possible environmental causes. Consecutive patients who were referred to the University Hospital at Pointe a Pitre with
parkinsonism from September 1996 to May 2002 were included. All cases were examined in a standardized manner by a neurologist with a special interest in
movement disorders and independently by 3 external
movement disorders specialists, using standard operational clinical diagnostic criteria. The subjects were 265 patients with Parkinson's syndrome living on Guadeloupe, four fifths of whom had been referred by primary care physicians and one fifth by neurologists. The
levodopa response was assessed after a minimum period of 1 month of continuous treatment. All patients had brain computed tomography or brain magnetic resonance imaging scans and detailed neuropsychological examinations. Of 265 patients, only 66 were classified as
Parkinson's disease, whereas 58 fulfilled the National Institute of Neurological Disorders and Stroke (NINDS) and Society for
Progressive Supranuclear Palsy (SPSP) criteria for
progressive supranuclear palsy, 100 had unclassifiable
parkinsonism, characterized by
dopa-unresponsiveness, marked axial rigidity, relative symmetry of parkinsonian features, early
dysarthria, and frontolimbic
cognitive impairment. Within this group, early postural instability,
dysarthria, a frontal behavior disorder, cortical or subcortical
atrophy, pyramidal signs, axial rigidity, and family history of
neurodegenerative disorders were associated with poorer prognosis. A very large number of unclassifiable cases of atypical
parkinsonism that do not fulfill operational criteria for
Parkinson's disease or other defined motor neurodegenerations has been observed on Guadeloupe. Most patients closely resemble descriptions of bodig from Guam. In both geographic isolates, an environmental cause has been discussed. Annonaceae fruits and
herbal teas are consumed on both islands. These plants contain several
neurotoxins, particularly
acetogenins, which induce dopaminergic neuron loss in animals. Neuronal death involves
cholinergic and dopaminergic cells of the substantia nigra and GABAergic neurons of the striatum, associated with microglial proliferation. The development of atypical
parkinsonism in Guadeloupe and probably elsewhere, could result from synergistic toxicity, but
acetogenins are probably the most potent
neurotoxin, acting as mitochondrial complex I inhibitor.