DiGeorge Syndrome (22q11.2 Deletion)
What is DiGeorge Syndrome (22q11.2 Deletion)?
DiGeorge syndrome is a genetic disorder caused by a missing piece of chromosome 22. This deletion happens during fetal development and affects multiple body systems. The condition is also called 22q11.2 deletion syndrome because it involves the loss of genetic material at position 11.2 on chromosome 22.
The missing genes affect how the thymus gland, heart, and parathyroid glands develop. The thymus is a small organ behind your breastbone that helps your immune system make T-cells, which are white blood cells that fight infection. When the thymus does not develop properly, your body produces fewer T-cells, leading to a weakened immune system.
DiGeorge syndrome affects about 1 in 4,000 to 6,000 births. Symptoms range from mild to severe depending on which genes are missing. Some people have only minor health issues while others face significant challenges with their heart, immune system, and development. Early diagnosis helps families plan for medical care and support.
Symptoms
- Frequent infections due to weak immune function
- Heart defects present at birth
- Cleft palate or other mouth and throat problems
- Low calcium levels causing muscle spasms or seizures
- Distinctive facial features including small ears or wide-set eyes
- Delayed speech and language development
- Learning difficulties or developmental delays
- Feeding problems in infancy
- Kidney abnormalities
- Behavioral or mental health challenges
Some children with DiGeorge syndrome have only a few mild symptoms while others experience severe complications. The condition often goes undiagnosed in people with milder symptoms until later in life. Many heart defects are detected before birth or shortly after delivery.
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Causes and risk factors
DiGeorge syndrome occurs when a small piece of chromosome 22 is missing. This deletion typically happens randomly during the formation of egg or sperm cells, or very early in fetal development. In about 90% of cases, neither parent has the deletion and the condition appears for the first time in the child. However, a parent with DiGeorge syndrome has a 50% chance of passing the deletion to each child.
The deleted section contains 30 to 40 genes that guide early development of several body systems. Risk factors for having a child with DiGeorge syndrome are not well understood because most cases occur randomly. Advanced parental age may play a small role but this connection is not proven. Genetic counseling helps families understand their specific situation and recurrence risk for future pregnancies.
How it's diagnosed
Doctors diagnose DiGeorge syndrome using genetic testing called fluorescence in situ hybridization or chromosomal microarray analysis. These tests detect the missing piece of chromosome 22. Diagnosis often begins when a baby is born with a heart defect or low calcium levels that prompt further investigation. Some cases are identified through prenatal testing when ultrasound shows heart or other physical abnormalities.
Blood tests help monitor key features of DiGeorge syndrome after diagnosis. Lymphocyte counts measure immune system function by showing how many T-cells your body produces. Low lymphocyte levels, especially low T-cell counts, indicate that the thymus is not working properly. Rite Aid offers testing that includes lymphocyte measurement to help monitor immune function in people with DiGeorge syndrome. Regular testing helps doctors track your immune health and adjust treatment as needed.
Treatment options
- Calcium and vitamin D supplements to manage low calcium levels
- Antibiotics to prevent infections in people with weak immune systems
- Immunoglobulin replacement therapy to support immune function
- Surgery to repair heart defects, cleft palate, or other structural problems
- Thymus transplant in severe cases of immune deficiency
- Speech therapy and developmental support for learning delays
- Physical therapy to address muscle tone and motor skills
- Mental health counseling and behavioral support
- Regular monitoring by specialists including cardiologists and immunologists
- Live vaccines may be avoided in people with severe immune problems
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Frequently asked questions
DiGeorge syndrome is a genetic disorder caused by a missing piece of chromosome 22. This deletion affects the development of the thymus gland, heart, parathyroid glands, and other organs. The condition causes a wide range of symptoms including immune problems, heart defects, and developmental delays.
DiGeorge syndrome affects approximately 1 in 4,000 to 6,000 births. It is one of the most common genetic deletions in humans. The condition occurs equally in males and females and affects all ethnic groups.
Early signs often include heart defects detected at birth, low calcium levels causing seizures or muscle spasms, and feeding difficulties. Many babies also have distinctive facial features like small ears or wide-set eyes. Frequent infections may develop as the immune system shows weakness.
Yes, prenatal testing can sometimes detect DiGeorge syndrome. Ultrasound may show heart defects or other physical abnormalities that prompt genetic testing. Amniocentesis or chorionic villus sampling can confirm the chromosome 22 deletion during pregnancy.
The thymus gland does not develop properly in DiGeorge syndrome, leading to low production of T-cells. T-cells are white blood cells that fight infections. Low T-cell counts mean the immune system cannot defend against viruses, bacteria, and fungi as effectively as it should.
Lymphocyte counts are essential for monitoring immune function in DiGeorge syndrome. This test measures the number and types of white blood cells, particularly T-cells. Low lymphocyte levels indicate poor thymus function and help doctors determine if additional immune support is needed.
About 90% of cases occur randomly with no family history. However, if a parent has DiGeorge syndrome, each child has a 50% chance of inheriting the deletion. Genetic counseling helps families understand their specific risk and options for future pregnancies.
Many people with DiGeorge syndrome live full and productive lives with proper medical care. The severity varies widely from person to person. Early intervention, regular monitoring, and treatment of specific symptoms help people manage the condition and reach their potential.
A team approach works best for DiGeorge syndrome. This typically includes immunologists for immune problems, cardiologists for heart defects, endocrinologists for calcium issues, and developmental specialists. Regular coordination among these specialists ensures all aspects of the condition receive attention.
Testing frequency depends on symptom severity and age. Children with immune problems may need blood work every few months to monitor lymphocyte levels. Adults with stable symptoms might test once or twice yearly. Your doctor will create a monitoring schedule based on your individual needs.