| 22q11 deletion syndrome: Genetics | 3044.00000000000 | 22q11 deletion syndrome: Genetics | 22q11 deletion syndrome: Genetics | 2 | English | Genetics | Child (0-12 years);Teen (13-18 years) | Body | NA | Conditions and diseases | Adult (19+)
Caregivers | NA | | 2018-04-18T04:00:00Z | | | | | | 9.80000000000000 | 48.6000000000000 | 854.000000000000 | | Health (A-Z) - Conditions | Health A-Z | <p>Learn about the genetic causes of 22q11 deletion syndrome, risk factors and confirming diagnosis.</p> | <h2>What is 22q11 deletion syndrome?</h2><p>
<a href="/Article?contentid=3043&language=English">22q11 deletion syndrome (22q11DS)</a> is a genetic condition that affects about 1 in 2000 to 1 in 4000 children. 22q11DS is known by several other names including velo-cardio-facial syndrome (VCFS) and DiGeorge syndrome.</p><p>22q11DS can affect many parts of the body
<a href="/Article?contentid=3045&language=English">including</a>:</p><ul><li>the heart</li><li>the immune system</li><li>the palate (roof of the mouth).</li></ul><p>It can also affect how a person learns.</p> | | <h2>Key points</h2><ul><li>22q11DS is known by many names such as velo-cardio-facial syndrome and DiGeorge syndrome.</li><li>22q11DS is a genetic disorder. It results from a small missing piece of genetic material (DNA) on chromosome 22. This is called a deletion.</li><li>The 22q11 deletion happens most of the time by chance. In some families, the 22q11 deletion can be inherited from a parent.</li><li>Genetic testing on a small blood sample can help to make a diagnosis.</li><li>A genetic counsellor can help you understand the genetics of 22q11DS and the chances for it to happen in a child.</li></ul> | | | <h2>Causes of 22q11DS</h2><div class="akh-series"><div class="row"><div class="col-md-12">
<figure>
<span class="asset-image-title">The organization of genetic material</span>
<img src="https://assets.aboutkidshealth.ca/akhassets/What_is_a_gene_MED_ILL_EN.jpg" alt="Cell with chromosomes, which contain DNA strands with genes and nucleotides" />
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<h3>Chromosome deletion</h3><p>DNA carries a person’s
<a href="https://pie.med.utoronto.ca/htbw/module.html?module=genetics">genetic information</a>. DNA is organized into structures called chromosomes. Each cell of the body contains the same number of chromosomes and all of a person’s genetic information. Humans have 46 chromosomes arranged in 23 pairs, with two copies of each chromosome. </p><p>Chromosomes carry all of our genes. Genes determine how a person will grow and develop. Missing genetic information (such as a chromosome deletion) can lead to medical and developmental problems. How a person’s development or health will be affected depends on which genetic material is missing. </p></div></div></div><p>All chromosomes have a long (q) arm and a short (p) arm. People typically have two copies of chromosome 22. People with 22q11DS have a small piece of genetic material (genes) missing on the q arm of one of their two copies of chromosome 22. This is sometimes called a deletion. Even though it is small, the deletion of the 22q11.2 chromosome region involves many genes and can affect many parts of the body.</p>
<figure class="asset-c-80">
<span class="asset-image-title">22q11 deletion</span>
<img src="https://assets.aboutkidshealth.ca/akhassets/22q11_microdeletion_EN.jpg" alt="Chromosome 22 with missing genetic material" />
<figcaption class="asset-image-caption">This chromosome 22 pair shows a complete chromosome (A) and a chromosome with a deletion (B).</figcaption> </figure>
<h3>How did your child get 22q11DS? </h3><p>Most of the time, 22q11DS is the result of a new genetic deletion that occurs when a baby is conceived. This is called a de novo deletion and occurs by chance in either the mom’s egg or the dad’s sperm. A de novo deletion is not caused by anything the parents did before or during the pregnancy. For parents who have a child with a de novo deletion, the chance of having another child with 22q11DS is low. </p>
<figure class="asset-c-80">
<span class="asset-image-title">
<em>De novo</em> deletion of 22q11DS</span><img src="https://assets.aboutkidshealth.ca/akhassets/22q11_de_novo_deletion_EN.jpg" alt="Chromosome distribution from unaffected parents resulting in spontaneous new gene deletion before baby is conceived" />
<figcaption class="asset-image-caption">Most of the time, 22q11DS is the result of a new genetic deletion in the egg or sperm before the baby is conceived. This is called a
<em>de novo</em> deletion and occurs by chance.</figcaption>
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<p>In some people with 22q11DS (about 10%), the deletion is inherited from a parent. Sometimes a parent might not know that they have 22q11DS until after they have a child diagnosed with this condition. A person who has 22q11DS has a 50% chance (1 in 2) of having a child with 22q11DS.</p>
<figure class="asset-c-80">
<span class="asset-image-title">22q11DS inherited from a parent</span>
<img src="https://assets.aboutkidshealth.ca/AKHAssets/IMD_22q11_inheritance_EN.jpg" alt="Chromosome distribution from an affected parent with 22q11 DS and an unaffected parent, producing two possible combinations" />
<figcaption class="asset-image-caption">22q11DS is caused by a deletion in chromosome 22. A person will have 22q11DS if one chromosome 22 in the pair has the deletion. In this example, the parent with 22q11DS has one chromosome 22 with a deletion and one intact chromosome 22 (without a deletion). If the baby inherits the intact chromosome 22, then the baby will not have 22q11DS. If the baby inherits the chromosome 22 with a deletion, then the baby will have 22q11DS.</figcaption>
</figure>
<p>You can speak to a genetic counsellor to discuss information regarding how 22q11DS happened in your family and your chances of having a child with 22q11DS.</p> | | <h2>How 22q11DS is diagnosed</h2><p>If the doctor <a href="/Article?contentid=3043&language=English">suspects that a child has 22q11DS</a>, they may order genetic testing. Today, three different tests are able to detect 22q11DS. Each requires a small sample of blood. Some tests look for the 22q11 deletion; others look generally at the chromosomes structures for any deletion or duplication of genetic material. </p><p>Only one of these tests is typically needed to make a diagnosis of 22q11DS. The test that is ordered by your child's doctor is chosen based on your child’s presentation. </p><p>It usually takes several weeks to get these test results back depending on the test chosen and the laboratory. Ask your health-care provider about your specific situation.</p><p>These tests include:</p><h3>FISH (fluorescent in situ hybridization)</h3>
<p>Fluorescent In Situ Hybridization (FISH) is a test that looks specifically for a deletion on chromosome 22. This test can miss small or atypical 22q11 deletions.</p><h3>Chromosomal microarray </h3><p>Chromosome microarray is a test that looks for extra or missing pieces across all the chromosomes. This test can detect small or atypical 22q11 deletions.</p><h3>MLPA</h3><p>MLPA is a DNA test that looks for missing or extra pieces in chromosome region 22q11. This test can detect small or atypical 22q11 deletions.</p> | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | https://assets.aboutkidshealth.ca/akhassets/What_is_a_gene_MED_ILL_EN.jpg | 22q11 deletion syndrome: Genetics | | False | | | | | | | | |
