Down syndrom


The Down syndrom, also Trisomy 21 called, is a chromosomal disorder. Affected individuals have three copies of chromosome number 21 - normally every human has only two. The excess genetic material influences the physical and mental development. The severity of the effects varies greatly from person to person. Read all important information about Down's syndrome here!

ICD codes for this disease: ICD codes are internationally valid medical diagnosis codes. They are found e.g. in medical reports or on incapacity certificates. Q90ArtikelübersichtDown syndrome

  • Symptoms and consequences
  • Causes and risk factors
  • Examinations and diagnosis
  • PrenaTest and panoramic test
  • Harmony test
  • treatment
  • Course and prognosis

Quick Overview

  • What is Down Syndrome? No disease, but an anomaly of the genome. This means that the genetic make-up of those affected deviates from the "normal state".
  • Causes: In all or some of the body cells of those affected, there are three (instead of two) copies of chromosome 21. Therefore, the Down syndrome is also called trisomy 21.
  • Frequency: most common deviation from normal chromosome number (numerical chromosome anomaly). An estimated one in every 650 babies is born with Down syndrome. About 30,000 to 50,000 people live in Germany.
  • Typical symptoms: et al short head, flat back of the head, round and flat face, slanting eyes with a delicate eye fold in the inner corner of the eye, usually open mouth with increased salivation, four-finger furrow, sandal gap, short stature
  • Possible consequences: et al Heart defects, malformations in the digestive tract, orthopedic problems (such as flatfoot), hearing and vision disorders, increased susceptibility to infections, sleep-disordered breathing, increased risk of leukemia, epilepsy, autoimmune diseases, autism, ADHD, etc., mental disabilities, but also special skills such as musical talent
  • Treatment options: targeted individual support (as early as possible), for example by means of physiotherapy, occupational therapy and speech therapy; operative treatment of organ and skeletal malformations; Treatment of comorbidities
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Down syndrome: symptoms and consequences

People with Down's Syndrome (trisomy 21) are usually on their own typical appearance detect. Characteristic Down syndrome symptoms are:

  • short head (brachycephaly) with flat back of the head, short neck and round, flat face
  • slightly oblique eyes with a delicate skin fold on the inner corner of the eye (epicanthus)
  • increased eye relief
  • bright, white patches of the iris ("brushfieldspots") - they disappear with age and the incorporation of color pigments in the iris
  • flat, broad nose root
  • usually open mouth and increased salivation
  • grooved tongue, which is often too big and protrudes from the mouth (macroglossia)
  • narrow, high palate
  • underdeveloped jaws and teeth
  • small, low-set, round ears
  • excess skin on the neck, short neck
  • short broad hands with short fingers
  • Fourfinger furrow (transverse furrow on the palm of the hand, starting under the forefinger and continuing to below the little finger)
  • Sandalenlücke (large distance between first and second toe)

Oblique eyes and a flat nose root are found not only in people with Down syndrome, but also in the tribe of the Mongols. Therefore, Down's syndrome was popularly referred to earlier as "Mongolism" and those affected as "Mongoloid". For ethical reasons, you should not use these terms anymore.

Other Down Syndrome features include poorly developed muscles (low muscle tone) and delayed reflexes. The body growth of those affected is slowed down, and they are below average size (short stature). In addition, pronounced connective tissue weakness makes the joints excessively mobile.

Down syndrome: health consequences

Trisomy 21 can affect your health. Particularly common trisomy 21 features are cardiac defect, They are found in about half of all people with Down syndrome. A common heart defect is the so-called AV (atrioventricular) channel. This is a septal defect between the atria and ventricles. It causes respiratory distress, stunted growth and recurrent pneumonia. In many cases, the cardiac septum between the heart chambers is not completely closed (ventricular septal defect).

Very often, Down syndrome is synonymous with Malformations in the gastrointestinal tract connected, such as narrowing of the small intestine or malformations of the rectum. Also hearing impairment and blurred vision are common.

Because the immune system is underdeveloped, those affected are more susceptible to infections, especially in the respiratory tract. For example, many Down Syndrome children are prone to middle ear infection, bronchitis and pneumonia.

The Trisomy 21 is in many cases with a sleep-disordered breathing (Obstructive sleep apnea), sometimes accompanied by snoring: The upper respiratory tract becomes slack and narrowed during sleep, resulting in short respiratory bursts. Each time, the oxygen saturation in the blood drops. The brain reacts with a wake-up pulse. Those affected fall asleep quickly and can not remember the next day most of the short waking phases. But they are often tired during the day, because the restful sleep is missing.

Another consequence of trisomy 21 is the increased risk of acute leukemia (a form of blood cancer): It is up to 20 times more than in children without this chromosomal abnormality. On chromosome 21 there are several genes that play an important role in the development of leukemia. The so-called acute myeloid leukemia (AML) is more common in Down syndrome than acute lymphoblastic leukemia (ALL) - in children without trisomy 21 it is exactly the opposite.

In addition to leukemia, too epileptic seizures (Epilepsy) as well Autoimmune diseases in Down syndrome more common than in the normal population. The latter include, for example:

  • Diabetes mellitus type 1
  • celiac Disease
  • Chronic rheumatic disease in childhood (Juvenile rheumatoid arthritis, also called juvenile idiopathic arthritis)
  • autoimmune thyroid disorders (such as Hashimoto's thyroiditis).

In addition, trisomy 21 is often observed orthopedic problems, These include, for example, malpositions in the area of ​​the neck and shoulder as well as on the hip (hip dysplasia), an unstable patella and malformations of the feet (such as flat foot).

In addition, people with Down syndrome have an increased risk for Behavioral problems or psychiatric conditions, for example, ADHD, autism, anxiety disorders as well as emotional problems and depression.

Down syndrome also affects the fertility out: Boys or men with trisomy 21 are usually infertile. Affected girls and women are fertile (albeit limited). The probability that they pass on the chromosome anomaly to the unborn child during pregnancy is about 50 percent.

Down syndrome: mental limitations

Down's syndrome is the most common cause of a congenital mental disability, Trisomy 21 children often learn to speak later than other children, partly because they usually hear worse. Their language is therefore sometimes difficult to understand. In many cases, those affected need more time to understand the facts. Those who have already learned something often have a hard time learning new things. The motor development is delayed - the children start crawling or walking late.

The intellectual abilities are more or less restricted. Some sufferers are severely mentally impaired (which is relatively rare), while others are almost average-minded. The following applies: The mental development of a Down syndrome child depends not only on its genetic make-up, but also on whether and to what extent it is promoted.

Down syndrome: special skills

Trisomy 21 does not just mean birth defects and limitations. People with Down syndrome have strong emotional abilities and a sunny nature: they are affectionate, tender, friendly and cheerful. In addition, many are musically talented and have a strong sense of rhythm.

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Down syndrome: causes and risk factors

Down's syndrome is on one Error in the production of germ cells (Ova or sperm):

Egg and sperm cells are formed by cell division from progenitor cells with normal double chromosome set (chromosomes = carrier of the genetic material). This double set of chromosomes includes 22 paired autosomes plus two sex chromosomes (XX in women and XY in men). Altogether that means 46 chromosomes.

The genetic information is normally distributed evenly over the developing germ cells during the process of division, which then each have a simple set of chromosomes (22 autosomes and one sex chromosome = 23 chromosomes). Thus, in a later fertilization by the fusion of egg cell and sperm again a cell with normal double set of chromosomes arise, from which then emerges over countless cell divisions of the child.

However, when dividing the 46 chromosomes into the resulting germ cells, mistakes can happen: sometimes the two copies of a chromosome accidentally end up in the same new germ cell. This then has a total of 24 instead of 23 chromosomes. If it melts later in the fertilization with another "normal" germ cell, the result is a so-called trisome cell - It contains three copies of the chromosome in question - for a total of 47 chromosomes. Down syndrome is Chromosome number 21 in triple (instead of twice) version available. Here are different doctors different forms of Down syndrome: Free trisomy 21, mosaic trisomy 21 and translocation trisomy 21.

Free Trisomy 21

All body cells are equipped with a third chromosome 21. It is almost always a spontaneous new mutation. That is, the free Trisomy 21 usually arises at random, that is, for no apparent reason. Approximately 95 percent All people with Down syndrome have a free trisomy. This is by far the most common variant of the chromosomal disorder.

This is how the free Trisomy 21 arises