It is thought that BDNF promoter methylation, BDNF/TrkB levels, BDNF-AS (BDNF antisense RNA), and TrkB isoforms can be used as biomarkers for early diagnosis and risk determination in neurodegenerative diseases where the deficiency of BDNF and TrkB signaling is thought to play a role. Here, NTRK2 is linked to neurodegenerative disease.