GTR Home > Conditions/Phenotypes > Lissencephaly 1

Disease characteristics

Excerpted from the GeneReview: LIS1-Associated Lissencephaly/Subcortical Band Heterotopia
LIS1-associated lissencephaly includes Miller-Dieker syndrome (MDS), isolated lissencephaly sequence (ILS), and (rarely) subcortical band heterotopia (SBH). Lissencephaly and SBH are cortical malformations caused by deficient neuronal migration during embryogenesis. Lissencephaly refers to a "smooth brain" with absent gyri (agyria) or abnormally wide gyri (pachygyria). SBH refers to a band of heterotopic gray matter located just beneath the cortex and separated from it by a thin zone of normal white matter. MDS is characterized by lissencephaly, typical facial features, and severe neurologic abnormalities. ILS is characterized by lissencephaly and its direct sequelae: developmental delay, intellectual disability, and seizures.

Available tests

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Check Associated genes and Related conditions for additional relevant tests.

Associated genes

  • Also known as: LIS1, LIS2, MDCR, MDS, PAFAH, PAFAH1B1
    Summary: platelet-activating factor acetylhydrolase 1b, regulatory subunit 1 (45kDa)

Clinical features

  • Intellectual disability
  • Hypoplasia of the brainstem
  • Seizures
  • Global developmental delay
  • Spastic tetraparesis
  • Pachygyria
  • Cerebellar hypoplasia
  • Lissencephaly
  • Ventriculomegaly
  • Heterotopia
  • Abnormality of the cerebral white matter
  • Postnatal microcephaly
  • Muscular hypotonia of the trunk
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