Background: The parkinsonian complex of Guam is an endemic neurodegenerative condition, which has been described only in the islands of the Guam archipelago and at the Kii peninsula of Japan. Up to now, only one "sporadic" case has been described (including the autopsy) in Japan. Study objective: To describe the clinical, laboratory and neurophysiological characteristics of the neurodegenerative disorder presenting in 4 patients with the complex syndrome of parkinsonism, amyotrophic lateral sclerosis (ALS), and dementia. Patients and methods: Four consecutive patients of Caucasian and Czech origin, presenting with the complex syndrome of slowly progressive parkinsonism, amyotrophic lateral sclerosis and dementia were examined clinically, including neuropsychological examination, and they were assessed using magnetic resonance imaging, electromyography and evoked potentials. The blood and CSF samples were also examined, and the levels of inflammatory and neurodegenerative markers (beta-amyloid, cystatin C and tau-proteins) were assessed. Results: The clinical phenotype in all four patients corresponded to the one described in the parkinsonian complex of Guam, including the presence of a cognitive deficit at the level of mild to severe dementia. The findings of EMG examination in all cases were those typically seen in ALS, and they met the El Escorial criteria. CSF levels of neurodegenerative markers (tau-protein) were elevated in all four patients. CSF levels of inflammatory markers were normal. Conclusion: The unique appearance of the syndrome typical for the endemic Guam complex in patients of Caucasian origin in Europe raises a question of endemicity and heredity of the Guam complex and deserves further research. (C) 2010 Elsevier B.V. All rights reserved.