The 22q11 microdeletion syndrome summarizes chromosomal anomalies that affect the long arm of chromosome 22 in gene locus 22q11 and manifest themselves in the form of malformation syndromes. In most cases, those affected suffer from a heart defect, fascial malformations and thymus hypoplasia. Treatment is symptomatic and focuses primarily on correcting malformed organs.
What is 22q11 microdeletion syndrome?
Chromosomal aberrations are structural or numerical anomalies in the genome. Most chromosomal aberrations represent a major defect in the genetic material. Chromosomal anomalies can be caused by a deletion, for example. With each deletion, part of the chromosome arm is lost. See AbbreviationFinder for abbreviations related to 22q11 Microdeletion Syndrome.
There are different clinical pictures and syndromes that are based on chromosomal aberrations. One of them is the so-called 22q11 microdeletion syndrome. As such, various disorders caused by changes in position 11 of chromosome 22 are grouped together. The most well-known of these disorders include DiGeorge syndrome and Shprintzen syndrome, also known as velo-cardio-facial syndrome.
The designation of the syndromes as CATCH-22 syndrome is just as common as the expression of the microdeletion syndrome 22q11. GiGeorge Syndrome and Shprintzen Syndrome are seamlessly related and share many symptoms. However, diseases from the group of microdeletion syndrome 22q11 are generally characterized by symptomatic diversity.
Causes
The cause of all 22q11 microdeletion syndromes are pathological changes on the long arm of chromosome 22 at position 11. More precisely, these changes are the smallest variant of the deletion. The loss of a section of DNA is called a deletion. The anomaly thus corresponds to a gene mutation.
For example, the microdeletion 22q11.2 leads to developmental field defects of the pharyngeal pouches and the gill arch due to base losses. As a result, the vessels close to the heart, the thymus and the parathyroid glands of the patients are affected by malformations. Since the term 22q11 microdeletion syndrome is a collective term for various deletion syndromes, not all of the symptoms described may occur in individual cases.
The expression can also differ significantly from case to case. All 22q11 microdeletion syndrome disorders have a partly hereditary basis, although new mutations can also occur.
Symptoms, Ailments & Signs
Due to microdeletions in gene locus 22q11, the patients of the syndromes suffer from more or less pronounced heart defects such as the ventricular septal defect. In addition to malformations of the vessels, especially in the region of the aortic arch, hypoparathyroidism can indicate the presence of the syndrome.
The missing or faulty development of the thymus can also be a symptom. There are usually additional facial malformations such as cleft lip and palate and micrognathia. Kidney involvement through to renal agenesis is also common. Some patients have a noticeably wide bridge of the nose, a particularly long bridge of the nose or a wide tip of the nose.
In addition, hypertelorism with an antimongoloid lid axis may suggest microdeletion syndrome. The same goes for a short philtrum or pinna dysplasia. Thymus hypoplasia can cause T-lymphocyte]] deficiency, which eventually leads to serious infections.
Due to hormone deficiencies, calcium deficiency can follow defects in the adrenal glands. Calcium deficiency, in turn, often develops into seizures. The severity and distribution of the symptoms depends on the individual case and, above all, on the type of microdeletion.
Diagnosis & disease progression
The first suspected diagnosis of a 22q11 microdeletion syndrome can be made on the basis of the combined occurrence of characteristic malformations. Malformations of the heart are often the first indication that, coupled with facial or glandular anomalies, can justify a suspected diagnosis. The floating harbor syndrome must be differentiated in the differential diagnosis.
Molecular genetic analyzes are used to confirm the diagnosis. Detection of a 22q11 deletion can be provided primarily by fluorescence in situ hybridization. The prognosis of patients differs from case to case. In particular, the organ involvement, the treatability and the severity of the individual malformations determine the course of the syndrome.
Complications
As a rule, those affected by the 22q11 microdeletion syndrome suffer from various malformations and malformations, which can significantly restrict and reduce their quality of life. First and foremost, the patients also suffer from a heart defect. If this is not treated, in the worst case it can also lead to cardiac death of the patient.
The face is affected by various malformations, so children in particular can suffer from teasing and bullying. A cleft palate develops and there are also problems with the kidneys. There are also problems with the ears, which can lead to a slight hearing loss. The 22q11 microdeletion syndrome also leads to cramps and thus to severe pain in the muscles.
It is not uncommon for the child’s parents and relatives to be affected by mental health problems or depression caused by the 22q11 microdeletion syndrome. A causal treatment of the syndrome is not possible. Therefore, only the symptoms can be limited, so that everyday life becomes more bearable for the person concerned. There are no complications. However, complete healing is usually not possible. The 22q11 microdeletion syndrome does not usually lead to a reduced life expectancy.
When should you go to the doctor?
The 22q11 microdeletion syndrome is a genetic disease whose symptoms are usually noticed immediately at birth. Disturbances in heart activity and the resulting heart rhythm problems are signs of an existing irregularity. Newborns often see the light of day with an optical deformity. Immediate medical treatment is required for a cleft lip and palate. Optical changes in the shape of the nose, abnormalities in the distance between the eyes or other facial deformities indicate a disease that needs to be examined and treated. In the case of an inpatient birth, the nurses and doctors present take the necessary steps for adequate medical care of the child in a routine process.
Midwives perform the same tasks in the case of a home birth and a birth in a birth center. In these cases, the parents do not have to take action themselves. If an unexpected spontaneous birth occurs without the presence of doctors or nursing staff, a medical examination of mother and child is generally necessary as soon as possible. An emergency service should be alerted so that adequate care can be provided. If the newborn child shows seizures, breathing problems or movement disorders, an intensive examination is necessary. In various medical tests, the cause of the symptoms is clarified and symptomatic treatment is initiated.
Treatment & Therapy
The cause of the 22q11 microdeletion syndrome lies in the genes. Although gene therapy approaches are currently being researched, they have not yet reached the clinical phase. For this reason, there is currently no therapy available that can eliminate the cause of the symptoms.
Instead of causal therapies, patients therefore receive symptomatic treatment combined with supportive measures. An interdisciplinary team of doctors cares for those affected. The focus of symptomatic treatment is initially the correction of all life-threatening malformations.
The malformations with the highest priority are usually heart defects or the non-placement of other organs. Invasive surgical procedures are usually the treatment of choice. For example, the thymus can be replaced by a transplant. In addition, calcium and vitamin D substitutions are initiated in the event of a corresponding deficiency.
Hormone substitutions may also be necessary in individual cases, depending on the symptoms. If there is a susceptibility to infections and the patient has to struggle with repeated infections, these infections are brought to a halt with conservative drug therapies.
Malformations of the face and purely plastic symptoms of a different kind can sometimes be treated with plastic surgery. However, these treatment steps are usually postponed, since the more serious defects have to be corrected first.
Outlook & Forecast
When making a prognosis, a distinction must be made between life expectancy and quality of life. For 22q11 microdeletion syndrome, the outlook is favorable under certain conditions. In this way, ill patients reach a normal old age, insofar as there are no serious accompanying circumstances such as a heart defect or an immune deficiency. Doctors try to correct organic malformations at an early stage through surgical interventions. If this is successful, the probability of a long-term freedom from symptoms increases. Only about four percent of all infants die from 22q11 microdeletion syndrome.
The quality of life is often reduced by visually perceptible flaws. Plastic surgery has meanwhile developed sufficient procedures to counter psychosocial stress. Such cosmetic surgeries take place after the correction of life-threatening defects. If accompanying therapies are used at an early stage, patients are most likely to be able to lead a self-determined life as adults. Others, on the other hand, need care in certain circumstances. It is usually possible to practice.
Patients with 22q11 microdeletion syndrome feel most comfortable in a stable environment. Therapeutic measures, medication and the use of aids are part of everyday life, either permanently or acutely. If parents forgo treatment, life expectancy and quality of life decrease significantly.
Prevention
For the prophylaxis of diseases from the group microdeletion syndrome 22q11 only a few preventive measures are available. Due to the fact that many associated syndromes are hereditary, genetic counseling in the family planning phase in particular can be described as a preventive measure in the broadest sense. If the results are appropriate, couples may decide not to have children and opt for adoption.
Aftercare
In the case of chromosomal aberrations such as the 22q11 microdeletion syndrome, those affected often have no or only very few follow-up measures available. She focuses on better managing the condition and improving quality of life. Since it is a genetic disease, it cannot be completely cured. Therefore, if you wish to have children, a genetic examination and counseling should always be carried out so that the chromosomal aberrations do not occur in the children.
Further treatment depends very much on the exact severity of the disease, so that no general prediction can be made. The life expectancy of those affected may also be reduced. Exertion and stressful or physical activities should definitely be avoided. Likewise, most of those affected are dependent on the help and support of their own family due to the chromosomal aberrations in order to master everyday life. Intensive and loving conversations are often necessary to avoid psychological upsets or depression. If necessary, a psychologist should clarify whether therapy should be used.
You can do that yourself
Due to the 22q11 microdeletion syndrome, patients suffer from birth from severe malformations that affect the heart, other internal organs and the face. The quality of life is initially impaired in particular by the heart defect. The parents accompany the sick child during necessary stays in the clinic. Various surgical interventions are usually required to correct the organic malformations.
Since the deformities in the face usually represent an aesthetic blemish for those affected and their parents, surgical interventions can also be used here if desired. For example, the doctors correct an existing cleft jaw and palate. In addition, those affected receive drug treatment, for example with regard to defects in the thymus. The parents pay attention to the correct dosage of the medicines, since the child patients cannot be expected to take responsibility for this.
If the patients are physically able, they usually attend a special school and receive valuable educational support there. Some children also attend a regular school as part of inclusion and are able to perform the services required there. Attending school often improves the quality of life because those affected make the acquaintance of other sick children. For the parents, the disease represents a major psychological challenge, which in some cases leads to psychological difficulties. It is then important that the legal guardians contact a psychotherapist.
