In these two latter studies it was noted, however, that BDNF was the serum factor most changed in ALS patients, although not achieving significance (Cao et al., 2022), and that a reduced BDNF level did correlate with patients that had the worst revised ALS functional rating scale (ALSFRS-R) scores (Tremolizzo et al., 2016). The gene discussed is BDNF; the disease is amyotrophic lateral sclerosis.