The Association between Linear Retinal Pigment Epitheliopathy and the ALS/Parkinsonism-Dementia Complex of Guam (S48.006)

Abstract

Objective: To report the association between asymptomatic linear retinal pigment epitheliopathy (LRPE) and the ALS/Parkinsonism-dementia complex (ALS/PDC) of Guam. Background Mortality for ALS/PDC has declined rapidly over the last 50 years suggesting an environmental aetiological factor. A unique linear depigmentation of the retinal pigment epithelium, resembling the tracks of a migrating parasite larva (i.e. larva migrans), was first recognized in ALS/PDC by Cox (1987), confirmed by Hanlon and Steele (1993) and has been reported in ALS/PDC of Japan (2003, 2006). LRPE has been suspected in a few Filipinos who migrated to Guam before 1950. Design/Methods: We examined the association between LRPE and ALS/PDC and dementia using two approaches. (a) We compared the proportion of LRPE in 1053 Chamorros of Guam seen since 1987 with and without ALS/PDC. (b) We followed-up 242 Guamanian Chamorros who were neurologically asymptomatic when examined for LRPE to confirm whether they have subsequently developed ALS/PDC or dementia by reviewing medical records in 2010. We used Cox9s proportional hazard models to calculate the hazard ratio (95% CI, p-value) for ALS/PDC according to LRPE status at baseline. Results: Cross-sectionally, LRPE was present in 50.8% of 299 patients with ALS/PDC or dementia but in only 26.2% of 754 age-matched subjects who were neurologically asymptomatic. (difference 24.6%, 95% CI 18.1,31.1, p Conclusions: LRPE is common among Guamanian Chamorros. LRPE is associated with ALS/PDC both cross-sectionally but also in prospective follow-up reducing the likelihood of reverse causation. LRPE may either be a marker of another aetiological environmental factor, or is one of several causal mechanisms that initiate ALS/PDC on Guam and in Japan. Supported by: CurePSP Foundation for PSP/CBD and related brain diseases. Disclosure: Dr. Afaisen has nothing to disclose. Dr. Duncan has nothing to disclose. Dr. Steele has nothing to disclose. Dr. Ben-Shlomo has nothing to disclose.