Routine laboratory work ups were unremarkable. Brain magnetic resonance imaging (MRI) with T2-weighted images show bilaterally mottled high signal intensities at medulla oblongata and bilateral high signal intensity at both cerebellar dentate nucleus (Fig. 1a and b). Meanwhile, there is no abnormal change in basal ganglia (Fig. 1c). In addition, a sagittal T1-weighted image demonstrates considerable cervicomedullary atrophy with intact pons (tadpole sign, Fig. 1d). 18F- 2b-carbomethoxy-3b-(4-iodophenyl)-N-(3-fluoropropyl) nortropane (FP-CIT) positron emission tomography (PET) of the patient show severely decreased FP-CIT binding not only in the bilateral putamen, but also in the bilateral caudate nucleus with a rostrocaudal gradient (Fig. 1e), compared with normal FP-CIT imaging finding of control (Fig. 1f). Anti-parkinsonian medications improved her motor symptoms considerably. However, based on abnormalities from the brain MRI, we could not exclude the possibility of comorbidity. We further performed next generation sequencing of customized panel, targeting 95 genes associated neurologic disorders by target capture method, resulting in known pathogenic heterozygous p.Arg70Trp variant (NM_002055.4:c.208C > T) in GFAP gene [2], confirmed by Sanger sequencing method. Until now, the patient has been followed up for 18 months, and she has shown a good responsiveness to anti-parkinsonian medications.
Fig. 1 Brain MRI and FP-CIT PET imaging of the patient. a, b Brain MRI with T2-weighted axial images show typical bilateral high signal intensity at both medulla oblongata and cerebellar dentate nuclei. c No major lesions in the basal ganglia and periventricular white matter. d A T1-weighted sagittal image shows tadpole shape cervicomedullary atrophy. e 3-dimensional [18F] FP-CIT PET shows severely decreased dopaminergic uptake in bilateral putamen and caudate nucleus with a rostrocaudal gradient. f FP-CIT PET in control shows normal dopaminergic uptake in bilateral putamen and caudate nucleus