Information on the following diseases can be found in the Related Disorders section of this report:

• Agenesis of the Corpus Callosum

Aicardi syndrome typically begins as involuntary muscle spasms between four months and four years of age. Other symptoms may include epilepsy, mental retardation, profound muscle weakness (hypotonia), an abnormally small head (microcephaly), abnormally small eyes (microphthalmia), ridges on the eyeball (colobomas), and/or abnormalities of the ribs and/or spinal column. Children of all ages with Aicardi syndrome have significant delay in motor development. Aicardi syndrome can be life-threatening during childhood due to complications from upper respiratory infections.

Aicardi syndrome is associated with a mutation of a gene on the X chromosome (Xp22.3). Most cases reported to date appear to be new mutations, and other family members have not had the malfunctioning gene.

Chromosomes, which are present in the nucleus of human cells, carry the genetic information for each individual. Human body cells normally have 46 chromosomes. Pairs of human chromosomes are numbered from 1 through 22 and the sex chromosomes are designated X and Y. Males have one X and one Y chromosome and females have two X chromosomes. Each chromosome has a short arm designated "p" and a long arm designated "q". Chromosomes are further sub-divided into many bands that are numbered. For example, "chromosome Xp22.3" refers to band 22.3 on the short arm of the X chromosome. The numbered bands specify the location of the thousands of genes that are present on each chromosome.

Aicardi syndrome only affects only females and, in very rare cases, males with Klinefelter syndrome with (XXY). It has been estimated that there are between 300 and 500 cases of AIC worldwide. There do not appear to be any predilections based on ethnicity or gender.

Symptoms of the following disorders can be similar to those of Aicardi Syndrome. Comparisons may be useful for a differential diagnosis:

Agenesis of the corpus callosum is a rare birth defect involving a partial or complete absence of the fibers that connect the cerebral hemispheres of the brain. Sometimes mental retardation may result, but other cases may be without symptoms and the child may have normal intelligence. The early symptoms of this disorder may be grand mal or Jacksonian epileptic seizures. These may occur during the first weeks or within the first 2 years of life. Other early symptoms may include: abnormal accumulation of cerebrospinal fluid around the brain (hydrocephalus), impairment of mental development, and/or delays in physical development. (For more information on this disorder, choose "Agenesis of the Corpus Callosum" as your search term in the Rare Disease Database.)

Diagnosis
Advanced imaging techniques, especially magnetic resonance imaging (MRI), show the presence or absence, in whole or in part, of the band of nerve tissue connecting the two halves of the cerebral cortex. The diagnosis of AIC may be confirmed by an eye examination that typically reveals small cream-colored cavities (lucunae) within the retina.

During MRI and CT scanning, a computer and magnetic waves or x-rays are used to create a film showing cross-sectional images of tissue structure.

Treatment
Anticonvulsant drug therapies may be used to suppress the seizures caused by Aicardi syndrome. These drugs include corticosteroids, adrenocorticotropic hormone (ACTH), prednisone, phenobarbital, phenytoin, and sodium valproate. Other treatment is symptomatic and supportive.

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222
TTY: (866) 411-1010
Email: prpl@cc.nih.gov

For information about clinical trials sponsored by private sources, contact:
www.centerwatch.com

A study sponsored by the University of California at San Francisco and the University of Chicago is designed to further the understanding of the genetic causes of agenesis of the corpus callosum with the ultimate hope of improving treatment for those affected. The clinical trial identifier number for this test is NCT00305305

McKusick VA, ed. Online Mendelian Inheritance In Man (OMIM). The Johns Hopkins University. Corpus Callosum, Agenesis of, with Chorioretinal Abnormality. Entry Number; 304050: Last Edit Date; 10/26/2005.

TEXTBOOKS
Schneider A. Aicardi Syndrome. In: NORD Guide to Rare Disorders. Lippincott Williams & Wilkins. Philadelphia, PA. 2003:509-10.

Menkes JH, Pine Jr JW, et al., eds. Textbook of Child Neurology. 5th ed. Williams & Wilkins. Baltimore, MD; 1995:279; 748.

Behrman RE, Kliegman RM, Jenson HB., eds. Nelson Textbook of Pediatrics. 17th ed. Elsevier Saunders. Philadelphia, PA; 2005:1988;2006.

Kanski JJ, ed. Clinical Ophthalmology. 4th ed. Butterworth-Heinemann. Oxford, UK; 1999:609.

JOURNAL ARTICLES
Prats Vinas JM, Martinez Gonzalez MJ, Garcia Ribes A, Maryinez Gonzalez S, Martinez Fernandez R. Callosal agenesis, chorioretinal lacunae, absence of infantile spasms, and normal development: Aicardi syndrome without epilepsy? Dev Med Child Neurol. 2005;47:419-20.

Aicardi J. Aicardi syndrome. Brain Dev. 2005;27:164-71.

Lim SA, Siatkowski RM. Peditric neuro-ophthalmology. Curr Opin Ophthalmol. 2004;15:437-43.

Chan V. Karvelas G, Jacob P, Carmant L. Early treatment of Aicardi syndrome with vigabatrin can improve outcome. Neurology. 2004;63:1756-57.

Rosser T. Aicardi syndrome. Arch Neurol. 2003;60:1471-73.

FROM THE INTERNET
NINDS Aicardi Syndrome Information Page. National Institute of Neurological Disorders and Stroke. Last updated April28, 2006. 3pp.
www.ninds.nih.gov/disorders/aicardi/aicardi.htm

Aicardi Syndrome. Multiple Congenital Anomaly/Mental Retardation (MCA/MR) Syndromes. Last updated: 27 October 1999. 2pp.
www.nlm.nih.gov/mesh/jablonski/syndromes/syndrome015.html

Aicardi Syndrome. Aicardi Syndrome Foundation. nd. 2pp.
Support and Contacts. Aicardi Syndrome Foundation. nd. 2pp.
Van den Veyver. Research. Aicardi Syndrome Foundation. nd. 4pp.
www.aicardisyndrome.org