The clinical, radiological, and biological features of Aicardi-Goutieres syndrome in 27 patients are reviewed from the Neuropediatric Unit, Hopital des Enfants Malades, Paris, France. The onset was within the first 4 months of life in 19. The head circumference was normal at birth, but 21 developed microcephaly during the first year. CTs showed severe, progressive brain atrophy in all patients, and variable calcification of the basal ganglia. CSF lymphocytosis was chronic and persisted beyond 1 year in 7 patients. High levels of interferon-a occurred in serum and CSF in 14. Nineteen patients who survived, 6 older than 10 years, are severely disabled. Neuropathological findings in 2 patients showed foci of necrosis and diffuse demyelination, without inflammation. An autosomal recessive inheritance is suspected. 
COMMENT. Aicardi-Goutieres syndrome is a familial, often fatal, progressive encephalopathy, probably autosomal recessive, characterized by basal ganglia calcification, microcephaly, chronic CSF lymphocytosis, with high levels of interferon-a in serum and CSF, but negative serological tests for common prenatal infections. The high levels of interferon are considered as a causal factor of the encephalopathy.