This uneven cortical surface is due to incomplete organogenesis which leads to no distinguishable layers in the cerebral cortex. Cobblestone lissencephaly shows a reduction and abnormalities in the grey matter of the cerebral cortex. Causes
Causes of lissencephaly can include viral infections of the uterus or the fetus during the first trimester, or insufficient blood supply to the fetal brain early in pregnancy. There are also a number of genetic causes of lissencephaly, including mutation of the reelin gene (on chromosome 7), as well as other genes on the X chromosome and on chromosome 17. Genetic counseling is usually offered if there is a risk of lissencephaly, coupled with genetic testing. Neural migration
Folding of the cerebral cortex is important in the development of overall brain function and cognitive abilities. Neuronal migration is the process by which neurons migrate to the final position in the brain during the development of the nervous system. This development of the nervous system occurs between 12 and 16 weeks of gestation. The neurons are created at the ventricular zone. The neurons then extend along the radial glia to reach the cortical zone. It is the disruption of the radial and tangential migration that causes reduced or absence gyri that is known as lissencephaly.The lack of gyri causing a smooth appearance of the cerebral cortex is due to abnormal neuronal migration in the developmental stages of the nervous system. The cause of lissencephaly has been linked to both genetic and non-genetic factors.
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):

Treatment
Treatment for those with lissencephaly is symptomatic and depends on the severity and locations of the brain malformations. Treatment is tailored towards the symptoms of the individual. Therapies for lissencephaly are to deal with the symptoms as the syndrome is congenital. Supportive care may be needed to help with comfort and nursing needs. Seizures may be controlled with medication and hydrocephalus may require shunting. If feeding becomes difficult, a gastrostomy tube may be considered. There are a number of organisations that raise awareness and funding for rare disabilities such as lissencephaly. They also seek to increase the quality of life for individuals living with related disabilities. In the United States, these organizations include Arc of the United States, National Organization for Rare Disorders, and March of Dimes. Prognosis
The prognosis for children with lissencephaly varies depending on the malformation and severity of the syndrome. Many individuals remain at a 3–5 month developmental level. Life expectancy is short and many children with lissencephaly will die before the age of 10. Some children with lissencephaly will be able to roll over, sit, reach for objects, and smile socially. Aspiration and respiratory disease are the most common causes of illness or death.