About ACC

What is Agenesis of the Corpus Callosum

Agenesis of the Corpus Callosum (ACC) is a rare neurological condition in which the Corpus Callosum, the major “pathway” for information being processed by the brain and which links the two hemispheres of the brain, fails to develop, either fully or only partially. The condition is usually diagnosed by CT (Computer Tomographic) or MRI (Magnetic Resonance Imaging) scan.

The effects of the condition are variable; ranging from normal development (where the condition may be undetected or be revealed incidentally), through mild developmental delay to severe learning difficulties, epilepsy, visual impairment and delayed motor development. There may be other brain malformations present, for example microcephaly (small brain) or hydrocephalus (obstruction of the flow of fluid in the head).

What is Aicardi Syndrome?

Aicardi Syndrome is a much rarer condition, which only affects girls. It involves ACC, together with severe learning difficulties, infantile spasms/seizures and choriorentinal lacunae (eye lesions).

Other problems associated with the condition are spinal or other bone abnormalities and hypotonia (floppiness). The condition is diagnosed by the means of an EEG (Electro Encephalogram) followed by a scan and detailed MRI examination of the eyes.

Please visit www.aicardisyndrome.org for more information.

Inheritance Patterns

For ACC, at present, this is uncertain. The cause may be genetic or it may be associated with other conditions which have a genetic basis. The precise nature of inheritance is not yet established so the risks of recurrence remain unresolved.

In the case of Aicardi Syndrome the cause is probably a new mutation in a gene on an X chormosome. The risk of recurrence is thought to be negligible.

Pre-natal diagnosis

ACC and AS may be undetectable through the more routine pre-natal examinations, but ACC may be detected by a scan at 18 weeks.