Germline mutations in the gene for DHODH lead to the rare Miller syndrome, which is associated with craniofacial and limb defects similar to those seen in children with foetal exposure to methotrexate.11 The overactivation of DHODH in MEN1-mutant cells appears to indicate particular dependence on this enzyme in such cells, and offers a relatively specific route to such oncogenic ‘addiction’. The gene discussed is DHODH; the disease is postaxial acrofacial dysostosis.