We report 2 siblings with the Aicardi-Goutieres syndrome (encephalopat
hy, basal ganglia calcifications, and persistent cerebrospinal fluid p
leiocytosis). The eldest sibling is severely retarded; his younger bro
ther has only mild, slowly progressive neurological deficits, To our k
nowledge, such a striking difference in clinical expression has not be
en reported previously. (C) 1997 by Elsevier Science Inc. All rights r
eserved.