The Leucine-rich repeat transmembrane neuronal proteins (LRRTMs) are differentially expressed in the nervous system and were recently found to instruct presynaptic and mediate postsynaptic glutamatergic differentiation, with LRRTM1 and LRRTM2 most potent at inducing presynaptic differentiation. Recent evidence suggests that LRRTM3 promotes the processing of amyloid-precursor protein (APP) by the β-secretase BACE, leading to the proteolytic production of the Aβ42 peptide that is the main component of amyloid plaques. Furthermore, LRRTM3 maps to a region of chromosome 10 linked to both late-onset Alzheimer's disease (AD) and elevated plasma Aβ42 levels, suggesting that LRRTM3 is a functional and positional candidate gene for AD.Synonyms: Leucine-rich repeat transmembrane neuronal protein 3