RAB11A and early-onset autosomal dominant Alzheimer disease: Enhanced processing of BACE1 substrates via increased targeting of BACE1 to Rab11-positive endosomes can also explain a functional link between NCAM2 and Alzheimer’s disease as suggested by studies showing that single nucleotide polymorphisms in the NCAM2 gene are associated with increased risk of late-onset AD [16] and increased levels of amyloid protein β in the cerebrospinal fluid [17].