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. Each LRRTM protein is a type I transmembrane containing ten extracellular leucine-rich repeats and a short intracellular tail and has a developmentally regulated pattern distinct from all others. LRRTM1 is a maternally suppressed gene that is associated paternally with handedness and schizophrenia.Synonyms: Leucine-rich repeat transmembrane neuronal protein 1