DCX mutation causes the disorganisation of neocortical layering in the cerebral cortex leading to a reduced folding. DCX is localised to the X chromosome and thus this mutation may be inherited however it still can appear randomly. As it is an X chromosome linked abnormality males who inherit the gene are more likely to be severely affected. Females who inherit the DCX mutation have a more mild version of the syndrome. ARX
The ARX gene encodes for the aristaless related homeobox genes which are active in the early embryonic development to control formation of many tissues and structure. ARX is involved in the development of the embryonic forebrain, migration and communication of neurons as well as migration and proliferation of interneurons. As ARX is expressed in the ganglionic eminences and the neocortical ventricular zone it can affect both radial and tangential migration. Similar to DCX, ARX is an X chromosome linked gene and is linked with other symptoms such as absence of portions of the brain, abnormal genitalia and severe epilepsy. RELN
Reelin (RELN) is an extracellular matrix glycoproteins that is secreted to help with the regulation of neuronal migration. Lack of RELN in mice has shown deficiencies in migrating neurons. In reported cases, lissencephaly caused by RELN deficiency has been more severe in anterior brain regions with a very small cerebellum. Viral infection
Lissencephaly has been recorded to have been caused by viruses and insufficient blood supply to the developing fetal brain. Cytomegalovirus (CMV) is a herpes related virus that can cause congenital defects.
In the past, life expectancy was said to be around two years of age. However, with advances in seizure control, and treatments for respiratory illness, most children live well beyond that age. With other advances in therapy and the broader availability of services and equipment, some children with lissencephaly are able to walk with varying degrees of assistance and to perform other functions once thought too advanced. See also
Gyrification
CEP85L - gene associated with posterior predominant lissencephaly in a 2020 study

References
External links

Lissencephaly at NINDS
GeneReviews/NCBI/NIH/UW entry on DCX-Related Disorders
OMIM entries on DCX-Related Disorders
GeneReview/NIH/UW entry on LIS1 Lissencephaly