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What is 22q11.2 deletion syndrome? (Back to Top)
- 22q11.2 deletion syndrome is a spectrum disorder encompassing what was formerly called DiGeorge syndrome, velocardiofacial syndrome, conotruncal anomaly face syndrome, and cases of Opitz G/BBB syndrome, and Cayler cardiofacial syndrome.[1] It is characterized by a variety of symptoms, including cleft palate, heart defects, unique facial characteristics, learning and feeding problems, immune system disorders, hypoparathyroidism, and scoliosis.[2] Symptoms can vary greatly from patient to patient. It is caused by a missing piece (deletion) of chromosome 22. The deletion occurs near the middle of the chromosome at a location designated q11.2.[1] Click here to view a diagram of chromosome 22.
- Last Reviewed: 7/3/2008
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What causes 22q11.2 deletion syndrome? (Back to Top)
- 22q11.2 deletion syndrome is caused by a missing piece of chromosome 22. The deletion occurs near the middle of the chromosome at a location designated q11.2.[1] Click here to view a diagram of chromosome 22.
Chromosomes are the structures that hold our DNA. Our DNA contains the instructions, called genes, that tells our bodies how to develop and function. Researchers are working to identify all of the genes that contribute to the symptoms of 22q11.2 deletion syndrome. They have determined that the loss of a particular gene called, TBX1, is probably responsible for many of the syndrome's symptoms. Additional genes in the deleted region likely contribute to the varied features of this syndrome.[1]
- Last Reviewed: 7/2/2008
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What are the symptoms of 22q11.2 deletion syndrome? (Back to Top)
- Symptoms of 22q11.2 deletion syndrome vary greatly from patient to patient. Symptoms may include:[3]
- Heart defects (74% of individuals)
- Palatal abnormalities (69% of individuals)
- Characteristic facial features (e.g., elongated face, almond-shaped eyes, wide nose, and small ears)
- Learning difficulties (70-90% of individuals)
- Immune system problems (75% of individuals)
- Low levels of calcium (50% of individuals)
- Significant feeding problems (30% of individuals)
- Kidney anomalies (37% of individuals)
- Hearing loss
- Laryngotracheoesophageal anomalies
- Growth hormone deficiency
- Autoimmune disorders (e.g., thrombocytopenia, juvenile rheumatoid arthritis, overactive thyroid, vitiligo, neutropenia, and hemolytic anemia)
- Seizures
- Skeletal abnormalities (e.g., extra fingers, toes, or ribs, wedge-shaped spinal bones, craniosynostosis)
- Psychiatric illness
- Eye abnormalities (e.g., ptosis, coloboma, cataract, and strabismus)
- Central nervous system abnormalities
- Gastrointestinal anomalies
- Preauricular tags
- Abnormal growths (e.g., hepatoblastoma, renal cell carcinoma, Wilm's tumor, and neuroblastoma)
- Last Reviewed: 7/2/2008
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Are thyroid problems associated with 22q11.2 deletion syndrome?
(Back to Top)
- Yes. Some people with 22q11.2 deletion syndrome develop Grave's disease, an autoimmune disease that causes the thyroid gland to produce too much hormone. Symptoms of Grave's disease may include anxiety, restlessness, insomnia, weight loss, and eye protrusion. Grave's disease may be treated with antithyroid medications, radioactive iodine, or surgery. Beta-blockers such as propranolol may be used to treat symptoms of rapid heart rate, sweating, and anxiety until the over active thyroid is controlled.[4]
- Last Reviewed: 6/25/2008
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Why might calcium be given to a child with 22q11.2 deletion syndrome? (Back to Top)
- Many people with 22q11.2 deletion syndrome develop hypoparathyroidism. Hypoparathyroidism is a condition in which little parathyroid hormone (PTH) is produced. This condition causes low levels of calcium and high levels of phosphorus in the blood. Common symptoms may include tingling, muscle cramps, pain, dry hair, brittle nails, dry, scaly skin, cataracts, weakened tooth enamel in children, muscle spasms called tetany (can lead to spasms of the larynx, causing breathing difficulties), and convulsions (seizures). The goal of treatment is to restore the calcium and mineral balance in the body.[5]
We recommend you discuss concerns regarding your child's treatment with his physician.
- Last Reviewed: 7/2/2008
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Are seizures associated with 22q11.2 deletion syndrome? (Back to Top)
- Yes. Some people with 22q11.2 deletion syndrome have seizures. The seizures may be evidence of an underlying central nervous system abnormality or can result due to low levels of the parathyroid hormone.[3]
- Last Reviewed: 7/2/2008
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How might seizures be treated? (Back to Top)
- There are many treatment options available for children and adults with seizures. It can be challenging for a family to find the medication or procedure that works best for their child. We suggest that you speak with your child's health care provider about working with a physician who specializes in treating epilepsy. The Epilepsy Foundation provides information that can assist you in finding a epilepsy specialist in your area at the following link.
http://www.epilepsyfoundation.org/drsearch.cfm
You can find more information on seizures and seizure disorders including information on treatment at the following links from MEDLINEplus, the National Library of Medicine Web site designed to help you research your health questions.
http://www.nlm.nih.gov/medlineplus/ency/article/003200.htm
http://www.nlm.nih.gov/medlineplus/ency/article/000694.htm
http://www.nlm.nih.gov/medlineplus/seizures.html
Additional information on seizures can also be found by visiting the following Web page developed by the National Institute of Neurological Disorders and Stroke (NINDS), part of the National Institutes of Health (NIH):
http://www.ninds.nih.gov/disorders/epilepsy/detail_epilepsy.htm
- Last Reviewed: 7/2/2008
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Can 22q11.2 deletion syndrome affect the central nervous system?
(Back to Top)
- Yes. 22q11.2 deletion syndrome can affect the central nervous system. Examples of central nervous system abnormalities, including brain abnormalities (e.g., cerebellar atrophy, polymicrogyria, enlarged sylvian fissures), neural tube defects, tethered cord, and seizures.[3]
- Last Reviewed: 7/2/2008
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Is 22q11.2 deletion syndrome rare? (Back to Top)
- Yes. 22q11.2 deletion syndrome affects an estimated 1 in 4,000 people. The condition may actually be more common than this estimate, however, because some people with a 22q11.2 deletion have few signs and symptoms and are not diagnosed with the disorder.[1]
- Last Reviewed: 7/2/2008
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Can 22q11.2 deletion syndrome be inherited? (Back to Top)
- Yes. In about 10 percent of cases, a person with this condition inherits the deletion in chromosome 22 from a parent. In inherited cases, other family members may be affected as well. The inheritance of 22q11.2 deletion syndrome is considered autosomal dominant because a deletion in one copy of chromosome 22 in each cell is sufficient to cause the condition.[1]
Most cases of 22q11.2 deletion syndrome are not inherited, however. The deletion occurs most often as a random event during the formation of reproductive cells (eggs or sperm) or in early fetal development. Affected people typically have no history of the disorder in their family, though they can pass the condition to their children.[1]
- Last Reviewed: 7/2/2008
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Since my son is having seizures now, could it mean that he has a different syndrome such as, hypoparathyroidism-retardation-dysmorphism syndrome? (Back to Top)
- Some individuals with 22q11.2 deletion syndrome do develop seizures. However, if you have questions regarding your son's diagnosis, we encourage you to speak with his healthcare provider. You may find it helpful to meet with a genetics professional, if you have not already done so. To find a genetics clinic near you, we recommend contacting your primary doctor for a referral.
The following online resources can also help you find a genetics professional in your community:
* GeneTests - A searchable directory of US and international genetics and prenatal diagnosis clinics. To locate genetics clinics in the United States, go to the following link and click on "Clinic Directory" to find a genetic service close to you.
http://www.geneclinics.org/
* ResourceLink - A database of genetics counseling services, searchable by location, name, institution, type of practice, or specialty. Hosted by the National Society of Genetic Counselors.
http://www.nsgc.org/resourcelink.cfm
* Genetic Centers, Clinics, and Departments - A comprehensive resource list for genetic counseling, including links to genetic centers and clinics, associations, and university genetics departments. Hosted by the University of Kansas Medical Center.
http://www.kumc.edu/gec/prof/genecntr.html
- Last Reviewed: 7/2/2008
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What is hypoparathyroidism-retardation-dysmorphism syndrome? (Back to Top)
- Hypoparathyroidism-retardation-dysmorphism syndrome is characterized by hypoparathyroidism, growth retardation, intellectual deficit, seizures, microcephaly (small head size), facial, eye, and teeth abnormalities, and short hands and feet. The syndrome is inherited in an autosomal recessive manner. It is caused by mutations in the tubulin-specific chaperone E (TBCE) gene.[6]
- Last Reviewed: 7/2/2008