SHISA9 and Alzheimer disease: While the roles of XYLT1, RNF220, KCTD8, and SHISA9 have not been previously linked to AD, their known functions related to nervous system development [65,66,67,68,69,70,71,72], white matter dystrophy [73], affective-related behavior [74], synaptic plasticity [75,76,77,78,79], visual integration [80], and schizophrenia [81] suggest potential roles in AD pathogenesis.