Lissencephaly-pachygyria spectrum

Dr Henry Knipe and A.Prof Frank Gaillard et al.

The lissencephaly-pachygyria spectrum is useful in describing the spectrum of diseases that cause relative smoothness of the brain surface and includes:

  • agyria: no gyri
  • pachygyria: broad gyri
  • lissencephaly: smooth brain surface

It is a basket term for a number of congenital cortical malformations characterised by absent or minimal sulcation.

Lissencephaly-pachygyria can be further divided into types I (classic) and type II, which differ in clinical presentation, underlying genetic abnormalities, and both microscopic and macroscopic (including imaging) appearances 2,6. They themselves represent a heterogeneous group of disorders. This article highlights a few generalities and outlines the differences between the two types, which are otherwise discussed separately:

Type I (classic) lissencephaly typically presents with marked hypotonia and paucity of movement.

Type II lissencephaly is associated with muscular dystrophy-like syndromes and includes Walker-Warburg syndromeFukuyama syndrome, and muscle-eye-brain (MEB) disease 2,6.

Although lissencephaly can be identified on all cross-sectional modalities (antenatal and neonatal ultrasound, CT and MRI), MRI is the modality of choice to fully characterise the abnormalities.

Type I and type II lissencephaly demonstrate vaguely similar appearances (thus the common term lissencephaly) but different macroscopic and imaging appearances are visible.

Type I (classic) lissencephaly can appear as the classic hourglass or figure-8 appearance or with a few poorly formed gyri (pachygyria) and a smooth outer surface. It is usually associated with band heterotopia.

Type II lissencephaly, on the other hand, has a microlobulated surface referred to as a cobblestone complex. Band heterotopia is not evident and the cortex is thinner than in type I.

Lissencephaly is derived from the Greek word λισσος (lissos), meaning smooth 7

Share article

Article information

rID: 1591
Section: Gamuts
Synonyms or Alternate Spellings:
  • Pachygyria
  • Agyria
  • Agyria-pachygyria spectrum
  • Lissencephaly
  • Lissencephaly-pachygyria spectrum
  • Agyria/pachygyria
  • Lissencephaly/pachygyria
  • Pachygyria/agyria
  • Pachygyria/lissencephaly
  • Pachygyria-lissencephaly spectrum
  • Pachygyria - agyria spectrum

Support Radiopaedia and see fewer ads

Cases and figures

  • Drag
    Case 1
    Drag here to reorder.
  • Drag
    Case 1
    Drag here to reorder.
  • Drag
    Inversion recovery
    Case 2
    Drag here to reorder.
  • Drag
    Drag here to reorder.
  • Drag
    Case 3
    Drag here to reorder.
  • Updating… Please wait.

    Alert accept

    Error Unable to process the form. Check for errors and try again.

    Alert accept Thank you for updating your details.