PRL and amyotrophic lateral sclerosis: In this study based on the UK Biobank cohort with a median follow-up of over 14 years, three key findings emerged (Fig 4): First, per SD reduction in PRL thickness was strongly associated with a 19% increased risk of ALS, while per SD increase in RPE thickness corresponded to a 20% higher risk, with these associations consistently observed 2, 4, and 6 years prior to ALS diagnosis.