A 57-year-old woman presented with a 3-month history of cognitive impairment, daytime somnolence, and violent sleep behavior. Her first- and second-degree relatives had similar symptoms prior to their premature deaths. Her MRI scan of the brain showed no significant abnormality. Electroencephalogram showed loss of slow-wave activity. Functional brain imaging performed with 18F-FDG PET was fused with her MRI scans. This demonstrated profound hypometabolism in bilateral thalami and the posterior cingulate cortex, which is pathognomonic for familial fatal insomnia. Hypometabolism in the temporal lobes suggests a long-standing course of the disease. Genetic testing confirmed a mutation of the prion-protein gene (PRNP).
From the *Department of Nuclear Medicine and Molecular Imaging, Singapore General Hospital;
†Department of Diagnostic Imaging, National University Hospital; and
‡Neurology (SGH Campus), National Neuroscience Institute, Singapore.
Received for publication January 26, 2018; revision accepted April 20, 2018.
Conflicts of interest and sources of funding: none declared.
Author contributions: W.Y.T. wrote the case report; Y.-L.T. edited and proofread the manuscript; P.R. obtained clinical history and performed investigations of the patient; W.X. interpreted the brain imaging and supervised the study.
Correspondence to: Wei Ying Tham, Department of Nuclear Medicine and Molecular Imaging, Singapore General Hospital, 11 Hospital Drive, Singapore 169610. E-mail: firstname.lastname@example.org.