Rapidly progressive dementia: Extending the spectrum of GFAP‐astrocytopathies?

Autoimmune glial fibrillary acidic protein astrocytopathy (GFAP‐A) is a steroid‐responsive meningoencephalomyelitis, sometimes presenting with atypical clinical signs such as movement disorders or psychiatric and autonomic features. Beyond clinical presentation and imaging, diagnosis relies on detection of GFAP‐antibodies (AB) in CSF. Using quantitative behavioral, serologic, and immunohistochemical analyses, we characterize two patients longitudinally over 18–24 months who presented with rapidly progressive neurocognitive deterioration in the context of GFAP‐AB in CSF and unremarkable cranial MRI studies. Intensified immunotherapy was associated with clinical stabilization. The value of GFAP‐AB screening in selected cases of rapidly progressive dementias is discussed.