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GENATLAS PHENOTYPE
last update : 07-11-2009
Symbol LIS1
Location 17p13.3
Name lissencephaly 1
Other name(s)
  • LIS1-associated isolated lissencephaly sequence (ILS),
  • LIS1-associated subcortical band heterotopia (SBH)/double cortex syndrome included
    • Corresponding gene PAFAH1B1
    Other symbol(s) ILS
    Main clinical features
  • isolated lissencephaly predominating in the posterior brain region (p>a gradient)
  • spectrum of agyria, mixed agyria/pachygyria, and pachygyria, characterized by an abnormally thick and poorly organized cortex with 4 primitive layers, diffuse neuronal heterotopia, enlarged and dysmorphic ventricles, and often hypoplasia of the corpus callosum
  • developmental delay and hypotonia , myoclonic jerks, absence seizures, febrile seizures, mental retardation, and reduced life expectancy
    • Genetic determination autosomal dominant
    chromosomal
    Prevalence account for approximately 75p100 of patients with lissencephaly ( Haverfield 2009)
    Related entries MDS
    Function/system disorder congenital malformation
    neurology
    mental retardation
    Type malformation
    Gene product
    Name platelet activating factor acetyl-hydrolase (PAFAH1B1)
    Mechanism(s)
    Gene mutationChromosome rearrangementEffectComments
    various types     intragenic mutations or deletions in 44 percent of cases
    deletion   haploinsufficiency microdeletions of the entire LIS1 gene,or microdeletions within the gene in 49 percent of cases
    Remark(s) PAFAH1B1 (LIS1) is involved in 87 percent of ILS cases
    Genotype/Phenotype correlations truncating or frameshift mutations had severe developmental delay with early-onset seizures, hypotonia, and spastic quadriparesis; patients with genomic deletions/duplications have the same severity; patients with missence or splice site mutation had a less severe clinical course