title: The natural history of cognitive dysfunction in late-onset GM2 gangliosidosis.
abstract: BACKGROUND
  Late-onset GM2 gangliosidosis (LGG) is a rare disease that is often considered in the differential diagnosis of adolescents and young adults who present with multiple realms of neurologic dysfunction. Cognitive disturbances are common but have not been systematically studied.
  
  
  OBJECTIVE
  To determine the natural history of cognitive dysfunction in patients with LGG.
  
  
  METHODS
  Case series and literature review.
  
  
  METHODS
  Urban tertiary referral clinic.
  
  
  METHODS
  Individuals with hexosaminidase A deficiency as the origin of LGG.
  
  
  METHODS
  Cognitive dysfunction, psychiatric symptoms, and cerebellar, upper motor neuron, lower motor neuron, or extrapyramidal symptoms and signs.
  
  
  RESULTS
  Historical and examination data from 62 patients were found. Forty-four percent of LGG patients had some degree of cognitive dysfunction. Cognitive dysfunction was associated with a greater number of other elemental neurologic deficits. In 21 patients with acceptable longitudinal information, 8 (38%) had a static cognitive disorder, whereas progressive dementia was evident in 13 patients (62%), including 2 of our cases with serial neuropsychological testing. Neuroimaging often showed nonspecific cerebellar and/or cerebral atrophy.
  
  
  CONCLUSIONS
  Cognitive dysfunction is a frequent manifestation of LGG. Patients who experience cognitive dysfunction are more likely to have a greater number of other neurologic manifestations of the disease. Cognitive dysfunction may take the form of static encephalopathy, but progressive dementia is more often encountered. The pathogenesis of cognitive dysfunction in this disease is unknown, highlighting the need for further study.
authors.affiliation: Department of Neurology, University of Colorado School of Medicine, Denver, Colo, USA. Lauren.Frey@uchsc.edu
authors.forename: Lauren C
authors.initials: LC
authors.lastname: Frey
authors.forename: Steven P
authors.initials: SP
authors.lastname: Ringel
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Filley
mesh_terms: D000328:Adult; D017668:Age of Onset; D003072:Cognition Disorders / Q000473:pathology / Q000503:physiopathology* / Q000523:psychology; D005260:Female; D020143:Gangliosidoses, GM2 / Q000473:pathology / Q000503:physiopathology* / Q000523:psychology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D012189:Retrospective Studies