For example, individuals with Miller syndrome, a rare genetic neurocristopathy affecting face and limb development, have mutations in dihydroorotate dehydrogenase (DHODH), the rate-limiting enzyme for pyrimidine de novo biosynthesis (Ng et al., 2010; Sporrij and Zon, 2021). The gene discussed is DHODH; the disease is postaxial acrofacial dysostosis.