DiGeorge syndrome is a chromosomal mutation that often has no genetic character. DiGeorge syndrome affects girls and boys with the same frequency. The main reason is considered to be the genetic defect of the 22nd chromosome, the absence of its defined section.
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DiGeorge syndrome, more precisely known as the term 22q11.2 "deletion syndrome", is a disorder caused by the absence of a small part of chromosome 22. This seemingly insignificant pathology causes wrong development of several parts of the body and various complications.
Signs and symptoms of DiGeorge syndrome (22q11.2) can vary in type and severity, depending on which parts of the body are deformed and how pronounced the defects are. Some signs and symptoms may be present at birth, while others may not be noticed until infancy or adolescence.
Signs and symptoms may include a combination of the following:
- Cyanosis - bluish tint of the skin, which is caused by a lack of oxygen in the blood due to a heart defect;
- Anomalies of the heart (often interrupted aortic arch, arterial gland and tetralogy of Fallot);
- frequent infections;
- Facial defects, such as an underdeveloped chin, low-set ears, wide eyes, or a narrow groove above the upper lip;
- cleft palate or other palate problems;
- Growth retardation;
- Difficulty eating, inability to gain weight, or gastrointestinal problems;
- breathing problems;
- Muscle weakness;
- developmental delay, such as a delay in sitting;
- speech problems, including hypernasal speech;
- behavior problems;
- hypocalcemia/hypoparathyroidism in early life;
- Immune system problems, including increased infections and pneumonia, due to reduced production of T-lymphocytes (white blood cells that fight infection).
Each person has two copies of chromosome 22, one inherited from each parent. If a person has DiGeorge syndrome (22q11.2 deletion), one copy of chromosome 22 is missing a segment containing about 30 to 40 genes.
Deletion of genes from chromosome 22 is usually a random process that can occur early in fetal development. Sometimes, but rarely, a deletion is inherited, passed down to a child from a parent who also has a deletion on chromosome 22, but may or may not have symptoms.
Complications of 22q11.2 deletion syndrome include:
- Heart defects – insufficient supply of oxygen-rich blood.
- Hypoparathyroidism – The four parathyroid glands in the neck regulate calcium and phosphorus levels in the body.
- Dysfunction of the thymus gland.
- Cleft palate - cleft palate - opening (cleft) in the oral cavity (palate) - with or without cleft lip.
- digestive disorders;
- Learning, behavioral and mental health problems, as well as problems with the development and functioning of the brain, which will lead to learning, social, developmental or behavioral problems.
- Autoimmune disorders.
Diagnosing DiGeorge syndrome is not difficult nowadays. It is mainly based on laboratory data. A chromosomal defect is detected by a genetic test, and this test is performed based on clinical signs.
Among other data, DiGeorge's syndrome is indicated by the deficiency of calcium, parathyroid hormone and T cells in the blood, the lack or absence of parathyroid glands and thymus.
There are two main types of tests available to prevent fetal syndromes during pregnancy (prenatal period): screening tests and diagnostic tests. Screening and diagnostic tests determine whether a fetus has a low or high chance of developing various syndromes.
If screening tests show that you are at high risk of having a baby with DiGeorge, it is recommended that you also have a diagnostic test to determine if the fetus has the genetic disorder.
1. Screening Tests – A prenatal screening test can determine if your baby is more or less likely to have birth defects, many of which are genetic disorders. These tests include blood tests, specific ultrasounds, and prenatal cell-free DNA screening.
2. Diagnostic tests – after the screening test, the final answer is given by the diagnostic test, which checks the genetic material of the fetus and therefore can also find out whether the fetus has a genetic disorder. Invasive and non-invasive prenatal diagnostic tests ((NIPT) Verasity, Veragen) are the only, safe and effective way to confirm the diagnostics.
Be aware that some diagnostic tests, such as chorionic villus sampling and amniocentesis, carry a small risk of miscarriage.
Learn more about prenatal diagnostics → (https://synevo.ge/prenatal-screening/)
Treatment is individual. Doctors of various specialties are involved in it. Although there is no cure for the syndrome, management of critical disorders such as heart defects or calcium in the blood is possible.
Treatment may be targeted to address this or that problem. In order to eliminate hypoparathyroidism, the patient is given supplements containing calcium and vitamin D, in the case of decreased thymus function, which is accompanied by frequent infections, anti-infective therapy is carried out.
In cases of severe thymus dysfunction or absence, when the child is at risk of severe infectious disease, a transplant of thymus tissue, specific bone marrow cells, or blood infection-fighting cells is recommended. Cleft palate or heart defects can be removed through surgery.
Children are treated with different methods for general development. A speech therapist, occupational therapist and others work with them.
A person with DiGeorge syndrome may need:
- Regular hearing tests, blood tests, heart scans, height and weight checks.
- Visits to a speech therapist to help overcome communication difficulties and better establish oneself in society.
- Orthopedic treatment for movement problems, as well as the use of devices such as shoe inserts (orthoses) to reduce pain in the feet
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