APP and Alzheimer disease: The sortilin-related receptor 1 SORL1 encodes SORLA, a key protein involved in amyloid precursor protein (APP) sorting and subsequently in degradation of amyloid-beta (Aβ) peptide, which aggregates and triggers AD pathophysiology.[6] In this study, we performed whole-exome sequencing (WES) to identify novel SORL1 mutations in 4 AD patients with parkinsonian and psychiatric features.