HCRTR2 and narcolepsy-cataplexy syndrome: Additionally, the T Cell Receptor Alpha Constant gene, involved in T-cell receptor α-constant, has been linked to narcolepsy, reinforcing the understanding that it is fundamentally an immune response-mediated condition.[27–29] A phase II trial of the orexin 2 receptor agonist for treating narcolepsy type 1 has been completed.