Agenesis of corpus callosum (ACC) may initially become evident through the onset of epileptic Seizures during the first weeks of life or within the first two years. However, not all individuals with ACC have seizures.
Other symptoms that may begin early in life are feeding problems and delays in holding the head erect. Sitting, standing and walking may also be delayed. Impairment of mental and physical development, and/or an accumulation of fluid in the skull (hydrocephalus) are also symptomatic of the early onset type of this disorder.
Non-progressive mental retardation, impaired hand-eye coordination and visual or auditory (hearing) memory impairment can be diagnosed through neurological testing of patients with ACC.
In some mild cases, symptoms may not appear for many years. Older patients are usually diagnosed during tests for symptoms such as seizures, monotonous or repetitive speech, or headaches. In mild cases it may be overlooked due to lack of obvious symptoms during childhood.
Some patients may have deep-set eyes and a prominent forehead. An abnormally Small head (microcephaly), or sometimes an unusually large head (macrocephaly), may be present. Tags of skin in front of the ears (pre-auricular skin tags), one or more bent fingers (camptodactyly), and delayed growth have also been associated with some cases of agenesis of corpus callosum. In other cases wide-set eyes (telecanthus), a small nose with upturned (anteverted) nostrils, abnormally shaped ears, excessive neck skin, short hands, diminished muscle tone (hypotonia), abnormalities of the larynx, heart defects, and symptoms of Pierre-Robin syndrome may be present. (For more information choose “Pierre-Robin” as your search term in the Rare Disease Database).
Aicardi syndrome, thought to be inherited as an X-linked dominant disorder, consists of agenesis of corpus callosum, infantile spasms, and abnormal eye structure. This disorder is an extremely rare congenital disorder in which frequent seizures, striking abnormalities of the eye’s middle coat (choroid) and retinal layers, and the absence of the structure linking the two cerebral hemispheres (the corpus callosum), accompany severe mental retardation. Only females are affected.
Andermann syndrome, identified in 1972, is a genetic disorder characterized by a combination of agenesis of corpus callosum, mental retardation, and progressive sensorimotor nervous system disturbances (neuropathy). All known cases of this disorder originate from Charlevois County and the Saguenay-Lac St. Jean area of Quebec, Canada. The gene causing this rare form of ACC was recently identified and testing for this gene (SLC12A6) is currently available.
XLAG (X linked lissencephaly with ambiguous genitalia is a rare genetic disorder in which males have small and smooth brains (lissencephaly), small penis, severe Mental retardation and intractable epilepsy. This is caused by mutations in the ARX gene. In females, these same mutations can cause ACC alone, whereas less severe mutations in males can cause mental retardation. Testing for this disorder is also clinically available.