NTRK2 and Parkinson disease: Tropomyosin receptor kinase A (TrkA) and Tropomyosin receptor kinase B (TrkB) are two other NTF receptors that are tightly associated with GM1, pointing to GM1′s essential role in maintaining the lifelong viability of cortical neurons, the loss of which has been implicated in Alzheimer’s disease (AD) as well as late stages of PD.