When we filtered the MS protein identification data for age-matched non-SCD controls against the list of expressed brain proteins listed in Table S3, we identified two brain-specific proteins: low density lipoprotein receptor-related protein 4 (LRP4; accession # O75096) and rabphilin (RPH3A accession# Q9Y2J0). Here, RPH3A is linked to Schnyder corneal dystrophy.