NLGN1 (Neuroligin 1): NLGN1 is a measure that reflects the presence and function of a key protein in the nervous system — Neuroligin 1, encoded by the NLGN1 gene. It plays a vital role in the formation and modulation of synapses, supporting synaptic specialization, strength, and plasticity. NLGN1 is critical for learning, memory, and overall brain function, and has been a focus in research on autism spectrum disorders and other neurodevelopmental conditions.