Neurophysiological findings in a case of carbohydrate-deficient glycoprotein (CDG) syndrome type I with phosphomannomutase deficiency

Eur J Paediatr Neurol. 1998;2(5):239-44. doi: 10.1016/s1090-3798(98)80037-8.


The carbohydrate-deficient glycoprotein (CDG) syndromes are multisystemic disorders involving the glycosylation pathway. The most common subtype is CDG syndrome type I (CDG I). In most CDG I patients a phosphomannomutase (PMM) deficiency has been recognized as the basic defect. We made a neurophysiological evaluation in an 8-year-old boy affected by CDG I with PMM deficiency. The evaluation included central and peripheral nervous system assessment [electroencephalogram (EEG), multimodal evoked potentials (MEP), somatosensory evoked potentials (SEP), visual evoked potentials (VEP), auditory brainstem response (ABR), electroretinogram (ERG) and motor and sensory nervous conduction velocity (NCV)]. We found a peculiar electrophysiological pattern characterized by slowly and mildly progressive motor NCV reduction; progressive impairment of ERG and VEP; slowing of background activity and sharp waves at the EEGs; late sensorineural abnormality of ABR; decreased amplitude and increased latency of SEP. To our knowledge this is the first report involving the neurophysiological aspects both at onset and during follow-up of a case of CDG I with proven PMM deficiency.

Publication types

  • Case Reports

MeSH terms

  • Atrophy / pathology
  • Brain / pathology
  • Child
  • Child, Preschool
  • Congenital Disorders of Glycosylation / diagnosis*
  • Electroencephalography
  • Electroretinography / methods
  • Evoked Potentials / physiology
  • Fatal Outcome
  • Glycosylation
  • Humans
  • Infant
  • Magnetic Resonance Imaging
  • Male
  • Neural Conduction / physiology
  • Peripheral Nerves / physiopathology
  • Phosphotransferases (Phosphomutases) / deficiency*
  • Psychomotor Disorders / diagnosis
  • Severity of Illness Index


  • Phosphotransferases (Phosphomutases)