AN UNWANTED FAMILY INHERITANCE: THE CASE OF THE RAPIDLY PROGRESSIVE DEMENTIA. H. Jasti 1 , R. Granieri 1 ; 1 University of Pittsburgh, Pittsburgh, PA LEARNING OBJECTIVES: 1) Recognize the clinical presentation of Creutzfeldt-Jakob disease (CJD). 2) Recognize the diagnosis of this condition. CASE INFORMATION: A 44-year-old white female with no significant past medical history was in her usual state of health until two months prior to presentation when she began to experience an unsteady gait and problems with memory. One month prior to presentation, she experienced a seizure and then, two weeks later, she developed a rapid decline in her function, starting with short-term memory loss and progressing to unresponsiveness. Family history was significant for a paternal aunt who, at the age of 49 years, had a similar decline in cognitive function over 14 months. Physical exam revealed an awake woman who was unresponsive to commands. Vital signs were within normal limits. Neurological exam revealed dystonic posturing of the head with spontaneous conjugate eye movements, myoclonic activity of the upper extremities, and increased motor tone bilaterally. DTR's were normal bilaterally in the upper and lower extremities, with downgoing plantar reflexes. Bilateral grasp and glabellar signs were elicited. ANA, ESR, RPR, and Lyme titers were negative. An LP and a MRI were non-revealing. An EEG revealed periodic sharp-wave complexes. CSF was positive for a mutation of the prion protein gene, confirming familial CJD. DISCUSSION: The prion diseases constitute a family of subacute, neurodegenerative diseases referred to as transmissible spongioform encephalopathies. Incubation periods last from months to years and symptoms gradually increase in severity and result in death over a period of months. CJD is the major transmissible spongioform encephalopathy in humans. While a sporadic form tends to occur after the sixth decade and has a rapidly progressive course of under a year, an inherited form usually manifests at a younger age and has a more protracted course. Cardinal clinical features include confusion and memory loss progressing to severe cortical dementia, ataxia, and myoclonus. The EEG typically demonstrates bilateral periodic discharges. Neuroimaging is helpful to exclude other etiologies, since there are usually no abnormalities. Elevated levels of the 14-3±3 protein in the CSF, which has a 96% sensitivity and specificity for CJD, are also helpful for the diagnosis. The defining pathology is the presence of "spongy" degeneration of cortical gray matter. At present, there is no effective treatment for CJD. The diagnosis of prion disease should be considered as part of the differential in cases presenting with dementia and an atypical movement disorder, especially if the rate of disease progression is rapid.