PT - JOURNAL ARTICLE AU - Hata Karamujić-Čomić AU - Annemieke J M Rozemuller AU - M Arfan Ikram AU - Cornelia M van Duijn TI - First participant diagnosed with Creutzfeldt-Jakob disease in the population-based Rotterdam Study was classified with mild cognitive impairment AID - 10.1136/bcr-2020-235509 DP - 2021 Mar 01 TA - BMJ Case Reports PG - e235509 VI - 14 IP - 3 4099 - http://casereports.bmj.com/content/14/3/e235509.short 4100 - http://casereports.bmj.com/content/14/3/e235509.full SO - BMJ Case Reports2021 Mar 01; 14 AB - Sporadic Creutzfeldt-Jakob disease (sCJD) is a rare, fatal, neurodegenerative disease caused by accumulation of abnormally folded prion protein. sCJD can have a long asymptomatic incubation period, with little known about this period. We describe the first-ever participant within the population-based Rotterdam Study diagnosed with sCJD. We retrieved clinical data from both the population-based Rotterdam Study and the National Prion Disease Registry. In 2011, a female participant of the Rotterdam Study was diagnosed with probable sCJD and registered into the Registry. Four months earlier, she was classified as having mild cognitive impairment based on assessment in the Rotterdam Study. Clinical deterioration was rapid, with the patient dying 7 months after the research centre visit. Postmortem brain autopsy confirmed the diagnosis of sCJD. In conclusion, we describe the first case diagnosed with sCJD who during diagnostic workup for sCJD was classified as having mild cognitive impairment in a population-based cohort study.