Abstract for presentation at The Australian and New Zealand Association of Neurologists Annual Scientific Meeting 2007

Alpers Syndrome with POLG mutations clinical, EEG and radiological features

  • Dr Matthew Hunter, Royal Children's Hospital Melbourne, Australia
  • Dr Mark Mackay, Royal Children's Hospital Melbourne, Australia
  • Dr Heidi Peters, Genetic Health Services Victoria, Murdoch Childrens Research Institute Melbourne, Australia
  • Renato Salemi, Murdoch Childrens Research Institute Melbourne, Azerbaijan
  • A/Prof David Thorburn, Murdoch Childrens Research Institute, Australia

    • Background/Objectives: Alpers syndrome is a rare autosomal recessive hepatocerebral degenerative disorder. We describe clinical, EEG and radiological findings in children with Alpers syndrome and POLG mutations.
    Methods: Retrospective review of 12 patients with Alpers syndrome and 2 pathogenic POLG mutations, seen between 1981 and 2007. Records were reviewed for clinical and EEG findings. Neuroimaging was reviewed in 10 children.
    Results: All children had developmental delay or regression and refractory epilepsy. Other symptoms included ataxia (6), visual disturbance (5), motor paresis (3) and tremor (2). Myoclonic and focal motor seizures were common often manifesting as status epilepticus. Eleven children had a total of 50 EEGs performed. All had absent/slow posterior dominant rhythms. Interictal discharges were seen in 9 children, involving the occipital lobes in 7. Discharges were unilateral focal (2), posterior bilaterally independent (2), multifocal (3), mixed focal and generalised (2). Two had preterminal burst suppression pattern. Seizures were captured during EEGs in 9 children. Five had electroclinical seizures, 2 had electrographic seizures, 2 had focal myoclonic seizures without an electrographic correlate. CT in 9 patients was normal (5) or showed abnormalities including low attenuation (3) and diffuse cerebral atrophy (1). Four children had MRIs. All showed abnormalities including T2 hyperintensities (4), restricted diffusion corresponding with T2 abnormalities (2) and focal atrophy (1). Lesions involved cortex (4), subcortical white matter (2), deep white matter (1) and deep thalamic grey matter (1). Regions affected included parietal lobes (4), occipital lobes (3), frontotemporal lobes (2) and primary sensorimotor cortex (2).
    Conclusions: Developmental regression and refractory focal motor or myoclonic seizures are consistent clinical features of Alpers syndrome with POLG mutations. Migratory T2/FLAIR signal abnormalities involving metabolically active occipital and sensorimotor cortical regions are characteristic MRI findings. Interictal and ictal EEG patterns are more variable although occipital cortical regions are commonly involved.

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