The manifestations of this x-linked disease are more drastic than SEH; males suffer from lissencephaly, while females suffer from band heterotopia.

The disease is autosomal-recessive and linked to the X-chromosome, so that men whose mothers are carriers of the gene manifest the disease.

Female mosaicism of the X chromosome has major implications for human health and disease and is the leading cause of female protection from X-linked genetic disorders.