SNCA and Schnyder corneal dystrophy: Despite of a few limitations that other biomarkers assessing combined tau, alpha synuclein, or TAR DNA-binding protein 43 pathologies are not evaluated, our study have several strengths as followings: Participants are consecutively recruited in South Korea using a comprehensive neuropsychological test battery and undergo various biomarker evaluations, allowing us to clarify cognitive and biomarker trajectories of SCD participants.