Eye and Brain (Jul 2020)
Etiology of Retinal and Cerebellar Pathology in Western Pacific Amyotrophic Lateral Sclerosis and Parkinsonism-Dementia Complex
Abstract
Peter S Spencer Department of Neurology, School of Medicine, Oregon Institute of Occupational Health Sciences, Oregon Health & Science University, Portland, OR, USACorrespondence: Peter S SpencerOregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239 Tel +1 503 209-0986Email [email protected]: To reexamine the etiology of a unique retinal pathology (linear and vermiform sub-retinal tubular structures) described among subjects with and without neurodegenerative disease in former high-incidence foci of Western Pacific amyotrophic lateral sclerosis and parkinsonism-dementia complex (ALS/PDC) in Guam (USA) and the Kii peninsula of Honshu island (Japan).Methods: Analysis of published and unpublished reports of 1) ALS/PDC and the retinal and cerebellar pathology associated therewith and 2) exogenous neurotoxic factors associated with ALS/PDC and the developing retina and cerebellum.Results: ALS/PDC retinal and cerebellar pathology matches persistent retinal and cerebellar dysplasia found in laboratory animals given single in utero or postnatal systemic treatment with cycasin, the principal neurotoxic component in the seed of cycad plants traditionally used for food (Guam) or oral medicine (Kii-Japan), both of which have been linked to the human neurodegenerative disease.Conclusion: ALS/PDC-associated retinal and cerebellar dysplasia could arise from in utero exposure to methylazoxymethanol, the genotoxic metabolite of cycasin that results from maternal ingestion of this azoxyglucoside. These results support the environmental toxic etiology of retinal and brain pathology in ALS/PDC.Keywords: amyotrophic lateral sclerosis, cycad, DNA damage, Guam, methylazoxymethanol, photoreceptor, retinal development, retinal dysplasia, retinal epitheliopathy, rosettes
