A type I interferonopathy characterized by severe developmental delay and progressive neurologic deterioration. Patients present in infancy with irritability and spasticity. Brain imaging shows diffusely abnormal white matter, cerebral atrophy, and intracranial calcification. Premature death has been associated with renal and/or hepatic failure. The disease is Monarch Disease Ontology term MONDO_0030362 (Aicardi-Goutieres syndrome 9). Also known as: AGS9.