Agenesis of the corpus callosum:Acongenitalabnormality (abirth defect)inwhich there is partial or complete absence (agenesis) of thecorpuscallosum, the area of thebrainwhich connects the twocerebral hemispheres(大脑的两个部分)。
Agenesis of the corpus callosumcan occur as a severesyndromein infancy orchildhood, as a milderconditionin young adults, or as anasymptomaticincidental finding.
If there are symptoms, the first ones are usually seizures followed by feeding problems and delays in holding the head erect, sitting, standing, and walking. Theseizuresmay constitute a very common disorder called infantile spasms. There may also be retardation in mental and physicaldevelopmentand impairment of hand-eyecoordination and visual and auditorymemory. Hydrocephalus is also acomplication. In mild cases, symptoms (such as seizures, repetitive speech, and/or headaches) may not appear for years.
Girls with agenesis of the corpus callosum may have a specific condition called Aicardi's syndrome in which there is severemental retardation, infantile spasms and chorioretinal lacunae. Agenesis of the corpus callosum can occur as an isolated condition or inassociationwith othercerebralanomalies (such as the Arnold-ChiarimalformationandDandy-Walker syndrome, Andermann syndrome withprogressiveneuropathy,schizencephaly,holoprosencephaly, and migrational anomalies). Agenesis of the corpus callosum is also associated with severalchromosomeanomalies, includingtrisomy13 and trisomy 18.
There is no standard course of treatment for agenesis of the corpus callosum. Treatment usually involves management of signs and symptoms such as hydrocephalus and seizures if they occur.
Theprognosis(前景)with agenesis of the corpus callosum is variable. The condition does not causedeathin the majority of patients. Although many children with the disorder lead normal lives and have average intelligence, careful neuropsychological testing reveals subtle differences in highercorticalfunction compared to individuals of the same age and education without ACC. Children with agenesis of the corpus callosum accompanied bydevelopmental delayand/orseizure disordersshould be screened formetabolicdisorders. The mental retardation associated with agenesis of the corpus callosum is not progressive.
