Also known as: Cree Encephalitis, Pseudo-TORCH syndrome, Microcephaly-intracranial Calcification syndrome (MICS)
Aicardi-Goutières syndrome (AGS) is a genetic brain disease which can be mistaken for the consequences of viral infections affecting a child in the womb. Most children with AGS show signs of the condition in the first few months of life. Features allowing a doctor to make a diagnosis of AGS include:
- calcification in the brain
- changes in the white nerve tissue of the brain
- raised levels of interferon-related proteins (chemicals produced by the body to fight viral infection – but in the case of AGS found in the absence of such infection) in the blood and the cerebrospinal fluid (CSF)
- distinctive ‘chilblain-like’ lesions on the hands and feet, which are usually worse in the cold
Last updated July 2018 by Professor Yanick Crow, University of Edinburgh, Edinburgh, UK.
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WHAT ARE THE SYMPTOMS?
In general terms there are two types of presentation in AGS. Some babies, especially those with AGS1 mutations (see ‘What are the causes?’), experience problems at or very soon after birth. Features include feeding difficulties, abnormal neurological signs, low platelets (blood cells involved in clotting), and liver abnormalities. In contrast, other children, develop normally for the first few weeks or months of life. They then experience the sudden onset of a period of intense irritability, cry a lot for hours at a time, sleep poorly, and can develop fevers without infection. During this period there is a loss of skills.
WHAT ARE THE CAUSES?
After a few months the disease process seems to ‘stop’. Many individuals with AGS are still stable in their late teens and early twenties. Typical neurological features of AGS include learning problems, stiffness of the limbs with poor body and head control, dystonia (impairment in muscle tone) of the limbs, and seizures (see entry Epilepsy). Although the neurological problems seen in AGS are often severe, a small number of children, usually those with AGS2 or AGS5-7 mutations, display good communication skills, and a few children can have completely normal intellectual development.
Seven different genes have been identified that, when damaged by a mutation, can cause Aicardi-Goutières syndrome (AGS). Only one gene is involved in any one family.
Will has a provisional diagnosis of AGS because he does not have the genetic markers for any of the known AGS genes. His diagnosis is based on his clinical presentation. He has interferonopathy, and there is at least one other child in the drug program like Will.
HOW IS IT TREATED?
The following treatments may be used for the management of AGS:
- management of seizures (which are quite common in more severely affected children) using standard protocols
- some children need tube or gastrostomy feeding because of difficulties with feeding secondary to the associated neurological problems
- chest physiotherapy and antibiotic treatment may be needed for respiratory complications, which can occur secondary to the associated neurological problems
- in some cases, treatments may be considered for chilblains
Surveillance includes the following:
- assessment for glaucoma (seen in a small percentage of cases)
- monitoring of the spine for the development of scoliosis (which can sometimes occur because of muscle imbalance)
- monitoring for signs of insulin-dependent diabetes mellitus (IDDM) and hypothyroidism (these are rare, but treatable, associations seen in a small percentage of patients)
- in the case of SAMHD1-related disease, there may be need for monitoring of the blood vessels in the brain with special scans