Gastaut-Geschwind Syndrome, Faciobrachial Dystonic Seizure, and Autoimmune Limbic Encephalitis.

Here we report a case of a 55-year-old male who had presented with recent falls and behavioral changes, including a heightened religious preoccupation, hypergraphia, and paranoid ideations. He was initially treated for psychosis but soon exhibited absence-like seizures, which were consistent with faciobrachial dystonic seizures. Workup for underlying infectious, immunodeficiency, and autoimmune causes revealed antibodies towards the leucine-rich glioma inactivated subunit of the voltage-gated potassium complex. The patient was treated with steroids and intravenous immune globulin with symptomatic relief. In retrospect, the patient met criteria for Gastaut-Geschwind (GG) syndrome, with notable features of hypergraphia and hyperreligiosity. This case illustrates how the GG syndromal pattern contributes to the suspicion of autoimmune limbic encephalitis and may expedite diagnosis and prevent the accumulation of disability.

DNA branch nuclease activity of vaccinia A22 resolvase.

DNA replication, recombination, and repair can result in formation of diverse branched DNA structures. Many large DNA viruses are known to encode DNA branch nucleases, but several of the expected activities have not previously been found among poxvirus enzymes. Vaccinia encodes an enzyme, A22 resolvase, which is known to be active on four-stranded DNA junctions (Holliday junctions) or Holliday junction-like structures containing three of the four strands. Here we report that A22 resolvase in fact has a much wider substrate specificity than previously appreciated. A22 resolvase cleaves Y-junctions, single-stranded DNA flaps, transitions from double strands to unpaired single strands ("splayed duplexes"), and DNA bulges in vitro. We also report site-directed mutagenesis studies of candidate active site residues. The results identify the likely active site and support a model in which a single active site is responsible for cleavage on Holliday junctions and splayed duplexes. Lastly, we describe possible roles for the A22 resolvase DNA-branch nuclease activity in DNA replication and repair.