Atypical parkinsonism and Annonaceae consumption in New Caledonia.

Recent studies have suggested a high incidence of atypical parkinsonism in patients living in or coming from different “exotic” areas.1–3 In some cases, environmental factors have been suspected, including the consumption of tropical fruits of the Annonaceae family containing alkaloids with possible neurological toxicity.1,4,5 Three Annonaceae fruits (Annona muricata, A. squamosa, and A. reticulata) are consumed traditionally in a French South Pacific island, New Caledonia. The aim of the present survey was to assess the proportion of typical versus atypical parkinsonism and Annonaceae consumption in this island. We undertook a 1-year study that included all patients with parkinsonism seen consecutively at the neurology department of the Noumea General Hospital. Secondary parkinsonism, such as drug-induced and vascular parkinsonism, was excluded by careful history taking, neurological examination, and brain computed tomography (CT) scan. Each patient was examined by a neurologist and classified according to international diagnostic criteria for idiopathic Parkinson’s disease (PD),6 progressive supranuclear palsy (PSP),7 Lewy body dementia (LBD),8 multiple system atrophy (MSA),9 and corticobasal ganglionic degeneration (CBD)10 or frontotemporal lobar degeneration.11 Patients who did not fulfill operational criteria for such disorders were considered as undetermined parkinsonism (UP), according to previous reports.3 Annonaceae consumption was assessed according to the following questionnaire: My consumption of sugar apple is (a) very regular (more than once a day); (b) regular (once a day); (c) quite regular (once or more a week); (d) occasional (less than once a week); and (e) rare or absent. For statistical analysis, regular (a b c) versus nonregular (d e) consumers were compared. All of 33 parkinsonian patients who attended the department were included (23 men, 10 women). Ethnic distribution was: 14 Caucasian, 9 Melanesian, 4 Wallisian (from Wallis and Futuna islands) and 6 Other. Of 33 patients, 18 were diagnosed as typical PD (54%), whereas 15 (46%) had clinical signs suggestive of atypical parkinsonism (2 probable MSA, 2 probable PSP, 1 LBD, and 10 UP). The typical/atypical parkinsonism ratio was comparable in the three main ethnic groups: Melanesian (4/9), Caucasian (7/14) and Wallisian (2/4). Eighteen subjects were regular Annonaceae consumers: 39% of the patients with typical PD (7/18) as compared with 73% of those with atypical parkinsonism (11/15, P 0.048, 2 test). All consumers had such a dietary habit for many years. Diagnosis in this study was based solely on clinical grounds, and misdiagnosis cannot be excluded in the absence of pathological confirmation. Moreover, the studied population is small and selection bias may have occurred. Nevertheless, it is interesting to note that, like in the French Western Indies,1,3 we observed an unusually high percentage of atypical cases among New Caledonian patients with parkinsonism. Some patients fulfilled diagnostic criteria for PSP, MSA, or LBD, but most (10/15) could only be classified as UP. Such patients had a clinical syndrome combining a relatively symmetrical akineticrigid syndrome unresponsive to levodopa with early dementia with prominent frontal lobe signs and postural instability. This is reminiscent of what has also been reported previously in Guadeloupean parkinsonism.3 Pseudobulbar and motoneuron signs, however, were rare or absent in patients from south Caledonia (1 and 0/10 UP patients, respectively). The small size of this population does not allow definite conclusions on causal factors such as genetic susceptibility or environmental factors. Nevertheless, as in Guadeloupe, heavy Annonaceae consumers were more frequent among patients with atypical parkinsonism. This is compatible with a putative toxicity of such fruits, as suggested by experimental data with the alkaloid totum from Annona muricata.12