Trisomy 18 or Edwards syndrome is a condition caused by a genetic defect in chromosome #18. Instead of being normally paired, the chromosome occurs in threes in the disease. So far no therapy is possible, the children usually die only a few days or weeks after birth.
What is trisomy 18?
Trisomy 18 is a genetic disease. Normally, every human being has a set of 23 pairs of chromosomes, or 46 individual chromosomes. During fertilization, the pairs of mother and father divide and the respective chromosomes combine again to form new pairs. For lathyrism definition and meaning, please visit eshaoxing.info.
In trisomy 18, one pair of the 18th chromosome does not divide. This creates a triple chromosome (free trisomy 18) in each cell with the new connection. Since the blueprint for the human body with all its functions is found on the chromosomes, a wrong system causes the corresponding disorders and malformations.
In addition to free trisomy 18, there are other rare variants of the disease, such as mosaic trisomy 18, in which the triple chromosome set is only present in some cells, and translocation trisomy 18, in which only fragments of the 18th chromosome are present three times. Trisomy 18 is also known as Edwards Syndrome, after its discoverer, human geneticist John Hilton Edwards.
The cause of trisomy 18 is not known. In the case of free and mosaic trisomy 18, it happens purely by chance that one of the chromosome pairs no. 18 does not divide and is then present in triplicate in the child’s cells.
The error occurs with no apparent cause during cell division. However, it is known that the probability of free trisomy 18 increases as the mother ages. In translocation trisomy 18, the father or mother is the carrier of the defect. This means that the disease can run more frequently in the family and that the potential for trisomy 18 can be passed on to offspring.
Symptoms, Ailments & Signs
Trisomy 18 is characterized by typical symptoms that can quickly provide an indication of the hereditary disease. Many physical malformations and mental impairments are particularly pronounced. The life expectancy of children with Edwards syndrome is greatly reduced.
Only about five to ten percent of those affected live to be more than a year old. However, some children have already reached and exceeded the age of ten. They are born with a low birth weight because physical development in the womb is already delayed. Striking are low-set ears, overgrown auricles, expansive back of the head, small chin and possibly a cleft lip and palate.
Bone malformations also occur on the ribs, vertebrae and pelvis. Many internal organs such as the heart, gastrointestinal tract or kidneys are often malformed. The same is also true for the brain. Patients also often suffer from breathing difficulties. The bulging forehead and the short eyelid fissures are also typical. Deformed feet ( clubfeet ) are often observed.
Eye malformations and malformations of the fingers also occur. So the index finger is often wrapped over the third and fourth fingers. Due to the brain malformation, the mental and motor development of the affected children is severely retarded. Children can only sit and crawl much later. As a rule, it is not possible for them to learn to speak.
Diagnosis & History
The course of trisomy 18 is very striking. Children are already lagging behind in their development in the womb. They weigh too little and have a too small head. The shape of the skull also deviates from the norm; the head is very expansive at the back.
There are also a variety of abnormalities on the face, such as a chin that is too small, malformations of the eyes or a cleft lip and palate. The organs are not formed normally. The heart, stomach, intestines and kidneys often have defects and do not function properly. The skeleton is also poorly formed, vertebrae or ribs are often missing or deformed.
Trisomy 18 can be diagnosed in the womb. During regular check-ups during pregnancy, the doctor usually notices growth retardation and a lack of movement. If trisomy 18 is suspected, a genetic test is usually carried out. For this purpose, amniotic fluid is removed and examined in an amniocentesis with a cannula through the abdominal wall.
Since there are cells of the embryo in the amniotic fluid, a chromosome determination can be carried out with them. With this examination, trisomy 18 can be diagnosed with certainty and the form of the disease can be determined.
Trisomy 18 leads to various disorders and symptoms. As a rule, physical and mental disabilities occur, which make the everyday life of the person concerned considerably more difficult. The patients suffer from severe developmental disorders and also from growth disorders. In many cases, they are therefore dependent on the help of other people in their everyday lives.
The malformations in the eyes caused by trisomy 18 can have a negative effect on the eyesight of those affected. Furthermore, a cleft palate develops, which can lead to problems when taking food and liquids. Many sufferers also suffer from a heart defect. If left untreated, this can lead to the death of the patient. The clubfoot can lead to restricted mobility.
Many children also suffer from bullying and teasing due to trisomy 18 and often develop physical complaints or depression as a result. The parents can also be affected by the psychological problems. Since a direct and causal treatment of trisomy 18 is not possible, no complications arise. As a rule, those affected die relatively early, so that the life expectancy of the patients is extremely limited.
When should you go to the doctor?
In Edwards syndrome, the person affected must definitely consult a doctor. It cannot heal itself, so medical treatment must be carried out in any case. The earlier the disease is detected, the better the further course is in most cases. Since it is a hereditary disease, a complete cure is not possible. If you want to have children, genetic counseling should also be carried out to prevent Edwards syndrome from recurring.
A doctor should be contacted if the person concerned suffers from various deformities and malformations. They appear mainly on the face and can make everyday life and the life of those affected significantly more difficult. In many cases, reduced intelligence can also indicate Edwards syndrome and should be evaluated by a doctor. Parents and relatives are often dependent on psychological treatment so that depression or other mental disorders can be prevented.
Treatment & Therapy
There is no therapy for trisomy 18. The damage and deformities are so serious that no treatments are possible. In the case of the somewhat milder mosaic trisomy 18, it is sometimes possible to keep the children alive a little longer through operations and treatments.
There are even a few isolated cases in which children with mosaic trisomy 18 have even reached adolescence. Free trisomy 18, on the other hand, is always fatal. The children usually survive only a few days or weeks. If the diagnosis of trisomy 18 is certain, the affected parents are often advised to have an abortion during the pregnancy.
Trisomy 18 cannot be prevented because the disease is caused by a genetic defect.
Follow-up care for trisomy 18 is primarily palliative. The aim is to enable the children to lead a pain-free or low-pain life during their usually short lifespan. Patients with Edwards syndrome should be examined regularly to assess their physical condition. Known physiological defects are regularly checked for changes by the attending physician.
If necessary, measures can be initiated if the condition deteriorates. Since almost all children with trisomy 18 die during the first months or years of life, psychological care for the parents is also part of good aftercare. Professional support for the family and good palliative care for the children make it easier for everyone involved to deal with the stressful situation.
Affected families are usually not only accompanied by doctors, but also by other professional groups such as psychologists, pastors and others. It should also be continued after the death of the child for as long as the person concerned wishes. No special precautions need to be taken for a renewed pregnancy, as the risk of recurrence is low. Many parents still consult a human geneticist and this can reduce their doubts and fears.
You can do that yourself
Since trisomy 18 is usually a very serious disease, the majority of children born die within the first few weeks of life. Even with treatment, only about 15 percent of girls survive to the age of ten, and adulthood is extremely rare. The main focus is therefore on relieving the symptoms and supporting the child by the family. Self-help groups and topic-related forums (eg Leona eV) enable them to exchange experiences with other affected people.
The specific options for coping with everyday life depend on the type and severity of the disability. In severe cases, i.e. with an unfavorable prognosis, there are specialized palliative care workers for children who support the parents. While treatment of the primary symptoms (e.g. organ damage) is left to the healthcare professionals, the resulting symptoms (e.g. difficulty eating) tend to fall within the realm of nursing. Some institutions (e.g. “Berliner Sternschnuppen”) offer free care courses for parents of disabled children. Specialized home care services can support and advise parents on home care.
In addition to the offers mentioned, offers for early support ( physiotherapy, ergotherapy ) should be used if possible. They can help relieve cramps and make motor or cognitive gains.