OMIM 257320 | ||
Lissencephaly 2, more commonly called Norman–Roberts syndrome, is a rare form of lissencephaly caused by a mutation in the reelin gene. A small number of cases have been described. The syndrome was first reported by M. Norman and M. Roberts et al. in 1976.
Lack of reelin prevents normal layering of the cerebral cortex and disrupts cognitive development. Patients have cerebellar hypoplasia and suffer from congenital lymphedema and hypotonia. The disorder is also associated with myopia, nystagmus and generalized seizures.
Norman–Roberts syndrome is one of two known disorders caused by a disruption of the reelin-signaling pathway. The other is VLDLR-associated cerebellar hypoplasia, which is caused by a mutation in the gene coding for one of the reelin receptors, VLDLR.
Disruption of the RELN gene in human patients is analogous to the malfunctioning RELN gene in the reeler mouse.