Tyrosine kinase receptors (TRKs) are a family of genes encoding neurotrophin receptors that include trkA, trkB, and trkC, which are related to development, differentiation, and survival of neural crest-derived neurons and central cholinergic neurons in normal tissue. The genes encoding trkA, trkB, and trkC are designated NTRK1, NTRK2, and NTRK3 and map to chromosomes 1, 9, and 15, respectively. A member of the TRK gene family, trkE, encodes a non-neuronal receptor for nerve growth factor. (from OMIM 600408) [ ]