Interestingly, both anti-RGMA and -RGMC antibodies bind to the RGMND, which interacts with GDF5 and BMP2, the latter of which were indicated as neurotrophic factors and are being investigated for possible treatment in neurodegenerative diseases, such as Parkinson’s disease (45, 46; for review, see ref. 47). This evidence concerns the gene GDF5 and Parkinson disease.