Creutzfeldt-Jakob Disease Presenting as Posterior Reversible Encephalopathy Syndrome.

Creutzfeldt-Jakob disease (CJD) is the most common human prion disease presenting with subacute cognitive decline. Common MRI findings for CJD include the T2 prolongation signal of the putamen and head of caudate. Diffusion-weighted MRI (DW-MRI) is considered to be the most sensitive technique for the detection of CJD-related abnormalities, especially for cortical changes. We report the case of a 77-year-old female who presented with dizziness, visual hallucination, and a rapid decline in her mental state shortly after a right knee surgery. Brain MRI with contrast showed cortical and subcortical T2 fluid-attenuated inversion recovery (FLAIR) hyperintensities in bilateral posterior temporal lobes and the left occipital lobe without an associated enhancement, suggestive of posterior reversible encephalopathy syndrome (PRES). Workup including metabolic, infectious, and vasculitic panels were all within normal limits. A few days later, she developed persistent myoclonus, and a continuous electroencephalogram (EEG) revealed multifocal epileptiform and generalized discharges, forming multifocal periodic discharges and generalized periodic discharges (GPDs). Cerebrospinal fluid (CSF) analysis was positive for 14-3-3 and elevated T-tau protein consistent with a diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD). This is a rare case of CJD presenting with a brain MRI resembling PRES. CJD may have various features on MRI, and a high degree of suspicion is required to confirm the diagnosis.

CRISPR/Cas9-mediated knock-in of an optimized TetO repeat for live cell imaging of endogenous loci.

Nuclear organization has an important role in determining genome function; however, it is not clear how spatiotemporal organization of the genome relates to functionality. To elucidate this relationship, a method for tracking any locus of interest is desirable. Recently clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) or transcription activator-like effectors were adapted for imaging endogenous loci; however, they are mostly limited to visualization of repetitive regions. Here, we report an efficient and scalable method named SHACKTeR (Short Homology and CRISPR/Cas9-mediated Knock-in of a TetO Repeat) for live cell imaging of specific chromosomal regions without the need for a pre-existing repetitive sequence. SHACKTeR requires only two modifications to the genome: CRISPR/Cas9-mediated knock-in of an optimized TetO repeat and its visualization by TetR-EGFP expression. Our simplified knock-in protocol, utilizing short homology arms integrated by polymerase chain reaction, was successful at labeling 10 different loci in HCT116 cells. We also showed the feasibility of knock-in into lamina-associated, heterochromatin regions, demonstrating that these regions prefer non-homologous end joining for knock-in. Using SHACKTeR, we were able to observe DNA replication at a specific locus by long-term live cell imaging. We anticipate the general applicability and scalability of our method will enhance causative analyses between gene function and compartmentalization in a high-throughput manner.