Developmental and epileptic encephalopathy-105 with hypopituitarism (DEE105) is an autosomal recessive disorder characterized by the onset of seizures and pituitary insufficiency in the first weeks or months of life. Affected individuals have profoundly impaired development with almost no acquisition of skills. They are hypotonic, unable to sit or speak, and have poor or absent visual fixation. Endocrine workup shows central pituitary dysfunction with low hormone levels. Brain imaging shows cerebral atrophy, thin corpus callosum, and small pituitary gland (Schanzer et al., 2021). For a general phenotypic description and a discussion of genetic heterogeneity of DEE, see 308350.