Lissencephaly - Classification

Classification

The spectrum of lissencephaly is only now becoming more defined as neuroimaging and genetics has provided more insights into migration disorders. There are around 20 different types of lissencephaly which make up the spectrum. Other causes which have not yet been identified are likely as well.

Different systems for classifying lissencephaly exist. One major distinction is "classic" (type I) vs. "cobblestone" (type II), but some systems add additional forms that fit into neither of these categories.

Some types of lissencephaly are described below (OMIM numbers are included where available):

Category	Types
Classic (or Type 1) lissencephaly – 607432	LIS1: lissencephaly due to PAFAH1B1 gene mutation, which subdivides into: type 1 isolated lissencephaly (601545) Miller–Dieker syndrome (247200) LISX1: lissencephaly due to doublecortin (DCX) gene mutation (300121) lissencephaly, type 1, isolated, without other known genetic defects
Cobblestone (or Type 2) lissencephaly	Walker–Warburg syndrome (236670), also called HARD(E) syndrome Fukuyama syndrome (253800) Muscle-eye-brain disease (MEB) (253280)
Other types	LIS2: Norman-Roberts syndrome (mutation of reelin gene, 257320) LIS3: TUBA1A, 611603 LISX2: ARX, 300215 Microlissencephaly (lissencephaly and microcephaly)

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