DOHH (deoxyhypusine hydroxylase) catalyzes the second and final enzymatic step in hypusine biosynthesis, converting the deoxyhypusine intermediate to hypusine on eukaryotic translation initiation factor 5A (eIF5A) 1. This post-translational modification is essential for eIF5A activation and efficient translation of specific gene products 2. DOHH functions as a monooxygenase requiring iron ion cofactors and operates in the cytosol [UniProt annotation]. Hypusinated eIF5A regulates translation of genes involved in critical cellular processes including MYC elongation, mitochondrial oxidative phosphorylation, and cellular proliferation 23. In cancer biology, DOHH expression is upregulated by extracellular aspartate signaling in lung metastases, promoting a translational program that enhances breast cancer aggressiveness through increased collagen synthesis 4. Pathologically, biallelic DOHH variants cause a neurodevelopmental disorder characterized by global developmental delay, intellectual disability, microcephaly, and facial dysmorphism, resulting from reduced enzyme activity and accumulation of non-hypusinated eIF5A 15. DOHH-related disorder patients frequently present with refractory epilepsy, particularly temperature-triggered seizures, with emergence typically between 2-5 years of age 5.