SPTLC1 and motor neuron disorder: Several publications highlighted the importance of L-serine in central nervous system (CNS) development and maintenance, and supplementation with L-serine was found to have a beneficial effect in motor neuron disease (Levine et al., 2017) linked to neuroprotection through the modulation of the endoplasmic reticulum (ER) stress response (Dunlop et al., 2018) and in hereditary sensory and autonomic neuropathy due to mutations in SPTLC1 (Fridman et al., 2019).