Longitudinal within-patient analyses demonstrated significant declines in pNfL and pGFAP following initiation of JAK inhibitor therapy, whereas the IFN score remained unchanged.<h4>Discussion</h4>pNfL and pGFAP are sensitive indicators of neuroaxonal and astroglial injury in AGS, capturing neurological disease burden and treatment-associated changes more accurately than the IFN score. The gene discussed is IFNA1; the disease is Aicardi-Goutieres syndrome.