Each month The Arc of New Jersey Family Institute spotlights a different developmental disability to help build awareness and educate others about the disorder. Learn more below.
What is Aicardi- Goutieres Syndrome?
Aicardi-Goutieres syndrome (AGS) is an inherited encephalopathy that affects newborn infants and usually results in severe mental and physical handicap. There are two forms of the syndrome: an early-onset form that is severe, and a late-onset form that has less impact upon neurological function. The early-onset form affects about 20 percent of all babies who have AGS. These infants are born with neurological and liver abnormalities, such as enlargement of the liver and spleen and elevated liver enzymes. Their jittery behavior and poor feeding ability mimic congenital viral infection.
Babies with later-onset AGS begin having symptoms after the first weeks or months of normal development, which appear as a progressive decline in head growth, weak or stiffened muscles (spasticity), and cognitive and developmental delays that range from moderate to severe. Symptoms last for several months, and include irritability, inconsolable crying, intermittent fever, seizures, and loss of developmental skills. Children may also have puffy swelling on the fingers, toes, and ears that resemble chilblains. A number of children have a noticeable startle reaction to sudden noise. For babies with the later-onset form, as symptoms lessen, there is no further worsening of the disease.
What are some symptoms of Aicardi-Goutieres Syndrome?
There are two forms of AGS: an early-onset form and a later-onset form. Symptoms for both begin in infancy, but at different times.
Symptoms of early-onset AGS
Infants with early-onset AGS have jittery behavior and poor feeding ability from birth. They also have neurological and liver abnormalities at birth, which can be detected through imaging tests. Early-onset AGS is the more serious form of the syndrome. The symptoms can become more severe over time, and can include smaller head size (microcephaly), liver inflammation, seizures and skin rashes.
Loss of myelin in early-onset AGS often leads to permanent damage to brain function, and to severe lifelong intellectual and physical disabilities.
Symptoms of later-onset AGS
Babies with later-onset AGS develop and behave normally for their first few weeks or months. When symptoms appear, they may include:
Intermittent, unexplained fever
Irritability or inconsolable crying
Skin problems, including chilblains (rash, lesions, or swelling on fingers, toes and ears that get worse in cold weather)
Weak or stiffened muscles
A decline in growth of the head
In later-onset AGS, these symptoms may last for several months. They then generally lessen and stabilize, but may leave persistent neurologic difficulties. Additionally, the immune dysfunction associated with AGS can affect many other organs of the body, sometimes in a life-threatening manner. This can include the lungs, the liver, the heart, the skin, blood cells and the kidneys.
What are the causes of Aicardi-Goutieres Syndrome?
AGS is caused by a mutation in one or more of a small group of specific genes. The mutation leads to a buildup of small pieces of DNA in the brain, which is thought to trigger the immune response that leads to the symptoms of AGS.
In most cases, AGS is inherited. That inheritance occurs only when both parents carry the genetic mutation, generally with no symptoms themselves. (This is called an autosomal recessive pattern of inheritance.) Pairs of each of our genes are inherited, one from each parent. If only one copy of a gene’s pair has the mutation, a person will not present with symptoms of AGS, but will be a carrier of AGS. When two carriers have children together, the odds are one in four that any child they produce will have AGS.
Less often, AGS can be caused by a single mutation inherited from an unaffected parent. In rare cases, the gene mutation associated with AGS is not inherited from a parent. It is simply a random mutation and is new in the person who develops the syndrome.
What is the treatment for Aicardi-Goutieres Syndrome?
Diagnosis of Aicardi-Goutières syndrome is made based on the physical symptoms, imaging of the brain, cerebrospinal fluid testing and the results of genetic tests.
Magnetic resonance imaging (MRI) of the brain is a key diagnostic tool of AGS, as it can detect patterns in brain tissue that are characteristic of the disease. When testing for AGS, your child’s doctor will look for areas of calcium buildup (calcifications) as well as shrinking or unusually small (atrophy) areas of the brain.
Cerebral spinal fluid (CSF) testing can reveal an increase in immune system activity that is typically found in AGS. The test is done by analyzing fluid taken from the spinal cord. This test alone is not used to make a diagnosis of AGS, but if the results are positive they can lead your child’s medical team to look for other signs of the syndrome.
Genetic testing can identify changes in one of the genes known to be associated with AGS. This analysis is done from a blood sample. The results, combined with other tests, can lead to a diagnosis of a specific type of AGS.