What is it about ?
Down syndrome is a birth defect. It is characterized by peculiar physical traits and can be accompanied by illnesses and other problems. Those affected suffer from intellectual disability, the limitations being mild to severe. With the right support for their independence, most of them can lead happy lives.
Down syndrome is also called trisomy 21. In the nuclei of the body’s cells, chromosome 21, instead of being in duplicate, is in triplicate; this is why we speak of “trisomy”. It is therefore a genetic anomaly; it occurs during cell division before or just after fertilization.
In addition, there are also forms of Down syndrome in which a certain fragment of chromosome 21 appears three times and is linked to another chromosome (usually chromosome 14). This phenomenon is called translocation and is inherited in about half of the cases. In this case, one of the two parents is the carrier. Genetic testing on the fetus is necessary to rule out the risk of recurrence of Down syndrome in subsequent pregnancies.
The risk of Down syndrome in babies increases with the age of the mother. Prenatal examination: A non-invasive prenatal test (TPNI test) or an invasive prenatal test (amniocentesis, that is, puncture of amniotic fluid) may be offered.
What is its frequency?
In Europe, Down syndrome affects 1 in 600 to 900 newborns. It is found in 1 in 100 newborns if the mother is 40 years of age or older.
Each year, around 45 babies with Down syndrome are born in Flanders. Often, but not always, future parents know this during the prenatal examination (screening for Down syndrome).
How to recognize it?
The characteristics of Down syndrome are as follows:
- Development is slower than in other children, both physically and intellectually. Children with Down syndrome are shorter, and they have a different growth curve. They have a tendency to be overweight, and 40 to 50% have an increased risk of congenital heart defects. This is why every baby suspected of having Down’s syndrome should have an echocardiogram and an electrocardiogram (ECG, the recording of the activity of the heart) during the first weeks of life.
- Eye problems: Myopia, hyperopia and amblyopia (lazy eye) can be solved with glasses. Cataracts (lens that becomes cloudy) and keratoconus (malformation of the cornea) also occur. Regular monitoring by an oculist is necessary.
- Hearing: The external ear canal is small, resulting in ear plugs due to the buildup of earwax. Also, among children with Down syndrome, six in ten hear less well. This is why they are given a hearing test during the first year of life and every year during childhood. This continues regularly into adulthood as well.
- Neurological and psychological symptoms due to problems with the brain and nervous system:
- epilepsy in 3% of children (infantile spasms) and up to 30% in adulthood;
- sleep apnea, requiring appropriate treatment;
- dementia of the Alzheimer type during growth;
- characteristics of autism in 10%, serious mental disorders and behavioral problems in a third;
- depressive symptoms: tendency to cry, loss of appetite, sleep disturbances, aggressiveness and mood swings are more common than in the normal population.
- Thyroid gland disorders: thyroid function often slowed down (hypothyroidism) and sometimes accelerated (hyperthyroidism). This requires regular monitoring of thyroid hormones TSH and T4 and anti-TPO antibodies with blood tests. The risk of diabetes mellitus is also increased.
- Birth defects of the gastrointestinal system, such as strictures (requiring surgery) and celiac disease (gluten intolerance). Constipation and gallstones are also more common than in the normal population.
- Due to urinary tract malformations, the risk of urinary tract infections is increased.
- Boys with Down syndrome often have small testicles. Corrective surgery is performed to prevent testicular cancer because the risk is increased. Fertility is almost always severely reduced.
- Joint problems due to mobility abnormalities and too low muscle tone (muscle weakness).
- Increased susceptibility to infections. Respiratory infections, ear infections and fungal infections are common, as are gum disease. The risk of leukemia is also increased.
- Skin conditions such as dry skin and seborrheic eczema or fungal infections.
How is the diagnosis made?
Usually, Down syndrome is detected during pregnancy during the prenatal examination. If not, the pediatrician and gynecologist will suspect Down syndrome soon after birth. The diagnosis is confirmed by a blood test with chromosome counting (in the nuclei of cells) and examination of the chromosomes. We can thus know whether it is the hereditary form or not.
What can you do ?
If Down syndrome is diagnosed during pregnancy, you, as the parents, need to decide whether you want to continue the pregnancy or terminate it. There may be social or financial reasons why you cannot take care of a child with Down syndrome. If you decide to keep the child, you must have the opportunity to prepare for the birth of a disabled child.
As a parent, family and caregiver, you play a very important role in the development of a child with Down syndrome. This depends not only on his dispositions, but also on the opportunities offered by his environment. With the right guidance and the right incentives, children with Down syndrome can learn much more than previously thought.
As a mother of a child with Down syndrome, you should know that breastfeeding definitely helps. It is good for the motor development and the general resistance of the baby.
It is essential that a child with Down syndrome is able to attend a rehabilitation program at home. As a rule, this is only possible with the supervision provided by a team of professionals and with the attention paid to the various areas of development. It is important that as parents you are helped.
What can the doctor do?
Preventive examination and regular monitoring of the child with Down syndrome is carried out by a doctor with experience in this disease (specialist). Early detection and treatment of health problems associated with Down syndrome is essential for health and life expectancy.
For neurological and psychiatric problems in people with Down syndrome, the usual treatments are usually used.
A thyroid gland that is too slow (hypothyroidism) is treated with thyroid hormones (thyroxine substitution). In case of constipation, diet and medication are prescribed.
Very good hygiene of the mouth and teeth is essential. Teeth (and gum) problems are indeed common in Down’s syndrome. In the event of a heart defect, preventive antibiotics are necessary before dental surgery. This prevents infection of the heart wall (endocarditis).
Abnormalities, often congenital, of the heart, stomach, intestines and testes should be treated early with surgery to prevent complications.
Women with Down syndrome are usually normally fertile. Contraception should therefore be considered in time.
Because of the high mobility of the joints, babies should not be put on their feet too early. It would be too great a mechanical stress. Sturdy shoes with laces are recommended. Support insoles are indicated for painful flat feet.
The benefits of treatment with antioxidants (selenium, zinc, vitamin E and vitamin B6) have not yet been demonstrated. The diet of people with Down syndrome should in any case be balanced and, if necessary, supplemented. High doses of vitamins are unnecessary, especially since they are ineffective.
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