NTRK2 and attention deficit-hyperactivity disorder: In this study of 341 referred ADHD assessed with the Child-Behavior Checklist [23], [33], we found suggestive but weak associations with BDNF (brain-derived neurotrophic factor), it’s preferred receptor (NTKR2, neurotrophic tyrosine kinase receptor, type 2), and a scaffolding protein (LRRC7, leucine rich repeat containing 7) anchoring a downstream protein kinase (CAMK2A, calcium/calmodulin-dependent protein kinase II alpha) required for initiation and maintenance of early-long-term potentiation [34], [35].