22q11.2 deletion syndrome is a genetic disorder with varying conditions present in each individual with the syndrome. In this syndrome, a tiny piece of chromosome 22 is missing. This can cause many medical problems. These problems may range from heart defects and developmental delays to seizures and effects on facial appearance, such as cleft palate (an opening in the roof of the mouth due to a birth defect).
In 22q11.2 deletion syndrome, a tiny piece of chromosome 22 is missing from the long arm of chromosome 22 at a location called q11.2.
Most people affected by the syndrome do not experience all the health problems that are associated with it. In general, health problems that are present due to 22q11.2 deletion syndrome can be managed with treatment, especially if they are detected early.
In the mid-1960s, an endocrinologist named Dr. Angelo DiGeorge recognized that a particular group of clinical features frequently occurred together, including the following:
The signs and symptoms of 22q11.2 deletion syndrome can vary from one affected person to another. For that reason, several disorders and collections of symptoms caused by this syndrome have had other names in the past. These names, some of which are still used occasionally, include:
In addition, some children with the syndrome were previously diagnosed with Opitz G/BBB syndrome or Cayler cardiofacial syndrome. Physicians now understand that these disorders all share the same genetic cause as 22q11.2 deletion syndrome.
About one in 4,000 people have 22q11.2 deletion syndrome. Some medical experts believe this number should be higher because some people with the chromosome defect have less severe symptoms that may not be diagnosed as 22q11.2 deletion syndrome. Thus, they are unaware they have the syndrome.
Most people with 22q11.2 deletion syndrome are missing about 30 to 40 genes. The exact function of many of these genes remains a mystery. But one gene, TBX1, probably accounts for the syndrome’s most common physical symptoms, including heart problems and cleft palate. Another nearby gene, called COMT, may also help explain the increased risk for behavior problems and mental illness in people with the syndrome.
About 90 percent of 22q11.2 deletion syndrome cases occur randomly at fertilization or early in fetal development. So most people affected with the disorder have no previous family history of it. However, they may pass the condition on to their children. The remaining 10 percent of cases are inherited from either the mother or the father. When the condition is inherited, other family members could also be affected. Because a person who has this chromosome deletion has a 50 percent chance of passing the deletion to a child, both parents are generally offered the opportunity to have their blood studied to look for the deletion.
The signs and symptoms of 22q11.2 deletion syndrome may vary widely, even among family members. At least 30 different signs or symptoms have been associated with this disorder, but most affected people only have some symptoms.
The most common symptoms include:
Facial features of children with DiGeorge syndrome may include the following:
The symptoms of 22q11.2 deletion syndrome may resemble other problems or medical conditions. Always consult your child's physician for a diagnosis.
In addition to a prenatal history, complete medical and family history, and a physical examination, diagnostic procedures for DiGeorge may include:
If a 22q11.2 deletion is detected in a child, then both parents are offered the FISH test to see if this deletion is inherited. In approximately 10 percent of families, the deletion has been inherited from one of the parents. Any individual who has this 22q11.2 deletion has a 50 percent chance, with each pregnancy, of passing it on to a child.
There is no cure for 22q11.2 deletion syndrome, but many of its related health problems can be treated. Parents can help their child by seeking early, competent care.
Specific treatment for DiGeorge syndrome will be determined by your child's physician based on the following:
Treatment will also depend on the particular features in any given child and may include the following:
Other common problems that may require treatment include:
A child’s doctor or parents may request an evaluation to determine what services are available to assist in the management of a child with 22q11.2 deletion syndrome.
A small percentage of children with severe heart defects and immune system problems caused by 22q11.2 deletion syndrome will not survive the first year of life. However, with the proper treatment of heart defects, immune system disorders, and other health problems, the vast majority of children with a 22q11.2 deletion will survive and grow into adulthood. These children will generally need extra help throughout school and will need long term care for their individual health needs.
Although it is not common, some children with the syndrome may have behavioral conditions such as autism, attention deficit disorder (ADD/ADHD), obsessive compulsive disorder (OCD), or anxiety. According to the Velo-Cardio-Facial Syndrome Educational Foundation, most individuals with the syndrome have some behavioral problems. The occurrence of psychiatric disorders is higher for adults with 22q11.2 deletion syndrome, but medical researchers are still investigating the exact nature and risk of these disorders.
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