What is Aicardi-Goutieres Syndrome?
Aicardi-Goutieres Syndrome is a disorder that mainly affects the brain, the immune system, and the skin. Most newborns with Aicardi-Goutieres syndrome do not show any signs or symptoms of the disorder at birth. However, about 20 percent are born with a combination of features that include an enlarged liver and spleen (hepatosplenomegaly), elevated blood levels of liver enzymes, a decrease in blood platelets (thrombocytopenia), and abnormal neurological responses. While this combination of signs and symptoms is typically associated with the immune system’s response to congenital viral infection, no actual infection is found in these infants. For this reason, Aicardi-Goutieres syndrome is sometimes referred to as a “mimic of congenital infection”.
Symptoms of Aicardi-Goutieres Syndrome usually appear within the first six months of life. Aicardi-Goutieres Syndrome is generally either fatal, or else it results in a persistent vegetative state in early childhood. Generally, the first symptoms observed are vomiting, feeding difficulties, and lack of progress in motor and social skills. A subset of patients has a later onset of disease, which usually occurs between six-twelve months of age, and is marked by loss of previously acquired motor skills and spasticity. The course of the disease is severe and progressive; death occurs in 25% of patients before 17 years of age. However, in some cases, there can be less impairment, and some retention of contact with surroundings and social interactions. Below is a list of symptoms that may be present for Aicardi-Goutieres syndrome, along with definitions as necessary. Please note that all of these symptoms are not present in all cases.
Symptoms may include:
- Microcephaly: abnormally small head
- Early progressive encephalopathy: abnormalities of the brain
- Lack of progress of motor and social skills; no or very poor contact with surroundings
- Feeding difficulties
- Spasticity: presence of spasms
- Dystonia: Abnormal muscle tone, characterized by prolonged, repetitive muscle contractions that may cause twisting or jerking movements of the body or a body part.
- Visual Inattention
- Ocular jerks: abnormal eye movements
- Sterile CSF lymphocytosis: cerebrospinal fluid that has elevated levels of lymphocytes (a certain cell of the immune system), but in which there are no indications of infection (sterility)
- Skin lesions of the toes, fingers, ear lobes looking like chilblains (itchy red swelling of the skin), puffy hands and feet, and cold feet. (40% of patients)
- Intracerebral calcification: presence of calcium deposits on a particular area of the brain
Genetic Basis of Aicardi-Goutieres Syndrome
Aicardi-Goutieres syndrome is inherited in an autosomal recessive manner. Briefly, it means that both parents of a child with Aicardi-Goutieres Syndrome carry a single copy of the defective gene responsible for the disease. The parents do not have any symptoms of disease, but with every child they have, there is a 25% chance that the child will receive two copies of the defective gene, which will result in the disease. The specific genetic defect involved in Aicardi-Goutieres syndrome has not yet been found, so therefore it is not possible to do prenatal testing by this method. There is a report suggesting that it may be possible to diagnosis the disease prenatally by an MRI, though this has not yet become a widely used tool for prenatal screening for this disease.
Changes in these genes are associated with Aicardi-Goutieres syndrome.
How is Aicardi-Goutieres Syndrome diagnosed?
Aicardi-Goutieres syndrome is difficult to diagnose, as many of the symptoms overlap with other disorders. The clinical symptoms of the disease are taken into consideration, as well as certain brain abnormalities seen by MRI (see our fact sheet on MRI for more information about this diagnostic tool). A sample of the cerebrospinal fluid (CSF) will be taken from a spinal tap. This fluid can then be tested for increased levels of a certain type of cell of the immune system (lymphocytes), a condition known as chronic lymphocytosis. These cells are normally only elevated during infection, so the combination of lymphocytosis combined with a lack of evidence of infection can support a diagnosis of Aicardi-Goutieres Syndrome. The CSF may also be tested for elevated levels of a molecule known as interferon-gamma, which can also be suggestive of this disease.
How is Aicardi-Goutieres Syndrome treated?
Treatment of Aicardi-Goutieres Syndrome is symptomatic and supportive. This means that you can treat the symptoms, but there is no cure for the disease.
How common is Aicardi-Goutieres syndrome?
Aicardi-Goutieres syndrome is a rare disorder. Its exact prevalence is unknown.
Are there other names for Aicardi-Goutieres Syndrome?
You may also hear Aicardi-Goutieres Syndrome called familial infantile encephalopathy, with calcification of basal ganglia and chronic cerebrospinal fluid lymphocytosis; this is simply a more medically descriptive name for the disease. Two other diseases (Cree encephalopathy and microcephaly, intracranial calcification syndrome (MICS)) share many common features with Aicardi-Goutieres, and therefore may be related.