Very recently, our group reported that the severe loss of dopaminergic midbrain neurons is correlated with significant elevation in serine enantiomers levels and downregulation of the astrocytic alanine serine cysteine transporter 1 (ASCT1), also known as SLC1A4 (Hofmann et al., 1994), in post-mortem caudate putamen (CPu) of PD patients with different Braak Lewy Body stage severity (3-4 and 6) compared to non-demented controls (Di Maio et al., 2023). Here, SLC1A4 is linked to Parkinson disease.