Given that protein folding in the endoplasmic reticulum (ER) is an oxidative process that relies on protein disulfide isomerases22 it is important to note that PHGDH increase was already identified in a white blood cell model of Marinesco‐Sjögren syndrome (MIM: 248800),23 a multisystemic disorder characterized by ER‐stress burden, myopathy and vulnerability of the peripheral nerves24 and that prolonged ER‐stress (which can be caused by oxidative stress) notoriously may result in initiation of apoptosis. The gene discussed is PHGDH; the disease is Marinesco-Sjögren syndrome.