Neuropsychological performance in patients with POLG1 mutations and the syndrome of mitochondrial spinocerebellar ataxia and epilepsy

Epilepsy Behav. 2009 Sep;16(1):172-4. doi: 10.1016/j.yebeh.2009.01.014. Epub 2009 Jan 28.


Mutations in the catalytic subunit of polymerase gamma (POLG1) produce a wide variety of neurological disorders including a progressive ataxic syndrome with epilepsy: mitochondrial spinocerebellar ataxia and epilepsy (MSCAE). Our earlier studies of patients with this syndrome raised the possibility of more prominent right than left hemisphere dysfunction. To investigate this in more detail, eight patients (six women, two men; mean age: 22.3 years) were studied. All completed an intelligence test (Wechsler Adult Intelligence Scale; WAIS), and four were also given memory tests and a comprehensive neuropsychological test battery. Patients with MSCAE showed significant cognitive dysfunction. Mean Verbal IQ (84.3) was significantly better than Performance IQ (71.8) (t=5.23, P=0.001), but memory testing and neuropsychological testing failed to detect a consistent unilateral dysfunction. Further studies are needed to define the profile and development of cognitive symptoms in this disorder.

MeSH terms

  • Adolescent
  • Adult
  • DNA Polymerase gamma
  • DNA-Directed DNA Polymerase / genetics*
  • Epilepsy / genetics*
  • Epilepsy / psychology*
  • Executive Function / physiology
  • Female
  • Humans
  • Intelligence Tests
  • Male
  • Memory / physiology
  • Mutation / physiology*
  • Neuropsychological Tests
  • Spinocerebellar Ataxias / genetics*
  • Spinocerebellar Ataxias / psychology*
  • Young Adult


  • DNA Polymerase gamma
  • DNA-Directed DNA Polymerase
  • POLG protein, human