ALDH18A1 and neurocutaneous syndrome: Recently, accumulative evidences have shown that mutations on the human P5CS gene (ALDH18A1) is one of the causes of hyperammonemia, neurocutaneous syndromes, and motor neuron syndrome (Baumgartner et al., 2005; Magini et al., 2019; Marco-Marín et al., 2020; Pérez-Arellano et al., 2010).