The p75NTR receptor is recently being proposed as a diagnostic biomarker of Alzheimer’s disease in serum (Jiao et al., 2015), and was also proposed as a prognostic, disease progression and potential pharmacodynamic biomarker for ALS and Huntington’s disease in urine, with increase in p75NTR ECD happening prior to symptoms appearance in ALS (Shepheard et al., 2014, 2017; Shi et al., 2021; Simmons et al., 2021). This evidence concerns the gene NGFR and Huntington disease.