Deep White Matter Cysts in a Patient with Aicardi-Goutières Syndrome and SAMHD1 Variants

Children appearing healthy at birth but developing disease symptoms within the first weeks or months of life are among the most challenging in the clinic.The deterioration of their condition calls for rapid diagnosis and swift action, while on the other hand a slowly unfolding, and probably incomplete clinical picture, renders any diagnosis difficult.Often an infection in utero is suspected, and tests for toxoplasmosis, rubella, cytomegalovirus, herpes simplex virus, among others, are initiated.In a recent review, the diagnostic yield of these tests turned out to be limited, however [Fitzpatrick et al., 2021].Alternatively, a neurologic disorder, such as Landau-Kleffner or Aicardi-Goutières syndrome (AGS), is presumed.This paradigm prompts extensive neurologic investigations and cranial computer tomography (CT) scans or magnetic resonance imaging (MRI) of the brain.Trying to diagnose a boy born in good condition, but soon showing poor growth and weight gain and developing unprovoked irritability, Oleksy et al. pursued both hypotheses [Oleksy et al., 2022].First, a screen for the most common congenital viral infections proved negative.Then, metabolic screens of urinary organic acids, serum amino acids and very-long-chain fatty acids, lysosomal enzyme activities, tests for congenital disorders of glyco-