PAFAH1B1 and classic lissencephaly: A number of studies have found that the gene PAFAH1B1 (encoding the protein LIS1) is essential for neuronal migration in a dose-dependent manner and is deleted in both MDS and ILS (Reiner et al., 1993; Lo Nigro et al., 1997; Hirotsune et al., 1998; Cahana et al., 2001; Gambello et al., 2003).