X-linked complicated corpus callosum dysgenesis is a genetic disorder characterized by dysplasia, hypoplasia or agenesis of the corpus callosum alongside variable intellectual disability and spastic paraplegia. Only 13 cases (all male) have been described in medical literature. Transmission is X-linked recessive. It is the mildest subtype of L1 syndrome.This condition differs from other L1 syndromes due to the fact that neither hydrocephalus, adducted thumbs, or speech difficulties are common in patients with the condition. Genetics
This condition is caused by X-linked recessive mutations in the L1CAM gene, located in the long arm of the X chromosome. Mutations involved in the milder variants of L1 syndrome (including X-linked complicated corpus callosum dysgenesis) usually work by changing the L1 protein structure. Cases
The following list comprises all cases of X-linked complicated corpus callosum dysgenesis described in medical literature (from OMIM):
1964: Menkes et al. describes 5 males from 4 sibships of a 2-generation American family. The males (all infants) had partial corpus callosum agenesis, severe intellectual disabilities, developmental delays, and epilepsy. The disorder first manifested right after birth, with recurrent seizures occurring hours after it. Out of these 5 babies, 3 had died. Post-mortem examination of one of the dead infants revealed chemical and anatomical abnormalities. 1983: Kaplan et al. describes 2 males from a 2-generation Canadian family. The proband was a 2 year old male, the first-born child of healthy, non-consanguineous Ashkenazi Jewish parents in their mid-20s, his pregnancy was uneventful (besides slight vaginal bleeding experienced by the mother sometime during her first three months of pregnancy).
Genetic testing revealed a missense mutation (p.P240L) in exon 7 of the L1CAM gene. == References ==