Pediatrics

Down syndrom

Synonyms in the broader sense

Trisomy 21
earlier, but outdated and discriminatory: Mongolism

definition

Trisomy 21 / Down syndrome is a syndrome that occurs due to a maldistribution of parental chromosomes in the child.
The distribution does not follow a specific inheritance, but rather occurs sporadically. Still, there are risk factors. Children with Down syndrome can have various physical and mental disabilities.

How do you recognize children with Down syndrome?

Children with Down syndrome already have physical characteristics at birth that are relatively specific to the condition. Affected children do not always have to have this. One of these features is an extra fold of skin around the neck. However, this disappears over time. Furthermore, birth weight is often lower than that of other children and also increases more slowly. The most noticeable feature, however, are the obliquely upward-pointing eyes, which have also given the disease the nickname Mongolism. This similarity is further emphasized by the often round face shape. An additional fold of skin can also appear between the eyes, but this does not impair vision. A narrow furrow on the palm of the hand is also typical. This four-finger furrow runs across the palm of the hand and occurs in almost all children with Down syndrome. However, not every child with such a furrow has Down syndrome.

In addition to these physical characteristics, children with Down syndrome often have cognitive impairments. Learning difficulties can often be identified, the severity of which can vary greatly between those affected. In general, there is a certain delay in development. Certain skills such as reading, writing or running can ultimately be developed by those affected just like other children, but often only at an advanced age. A trait that is often described is that children with Down syndrome are often very lovable and open-minded towards other people. Those affected also owe the name "angel children" to this characteristic.

You can find out more about the topic here: Problems with learning A-Z

Epidemiology / Occurrence

Trisomy 21 was first identified in 1866 by the English neurologist John Langdon Down described. The syndrome was named after him. However, it wasn't until 1959 that the French discovered Geneticist Lejeune the genetic cause of trisomy 21.
Today children with this chromosome maldistribution are born with an incidence of 1:700 born. This means that one in 700 newborns in Germany is born with Down's syndrome.

causes

The causes of trisomy 21 are, as the name suggests, a triple presence of chromosome 21 in the child's inheritance.
It is therefore a numerical, i.e. number-dependent, maldistribution of the chromosomes. Normally every person has two copies of all of their autosomal chromosomes (this includes all 23 chromosomes, except for sex chromosomes X and Y). These copies are passed on to the children. In Down syndrome, not one, but two copies of chromosome 21 are usually passed on from the mother to the child, so that the child has three copies.

The risk of such a maldistribution increases with the age of the mother. From the 35 years of age has the Mother at higher risk for a so-called nondisjunction. This means that the mother's chromosome pairs do not separate in order to be evenly distributed among the daughter cells.

There are different causes of trisomy 21. In the case described above, the additional chromosome 21 is also free (free trisomy 21). In 95% of the cases it is a new mutation. In other cases, which occur very rarely (approx. 5%), the 21st chromosome is on a different chromosome. This is known as translocation trisomy 21.

Complications

Children with Trisomy 21 / Down syndrome compared to the healthy population have a 20-fold increased risk of one leukemia to get sick.

Possible characteristics of Down syndrome

Many, but not all, children with Down syndrome may have certain characteristics:

Changes in the head and face area
- Round skull
- Outwardly rising ("mongoloid") lid axis
- Skin fold at the inner corner of the eye (epicanthus)
- Large distance between the eyes
- Flat, broad bridge of the nose
- Big tongue
- Deep set and rounded ears
- Short neck
- Narrow, high palate (speech disorders)
Changes in arms and legs
- short, broad hands
- Four-finger furrow (furrow on the palm of the hand that usually begins on the little finger side and extends between the middle and index finger (i.e. over 3 fingers), in Down syndrome up to between the index finger and thumb (i.e. over 4 fingers))
- Sandal gap (wide gap between big toe and second toe)
Other specifications
- intellectual disability, the severity of which varies greatly from person to person
- slowed reflexes
- Heart defect
- Malformations of the hip

Diagnosis of Down syndrome

Often the above-mentioned characteristics allow a suspected diagnosis, although one must under no circumstances assume that children with Down syndrome necessarily have all these characteristics. To confirm the suspicion of Down syndrome, a Chromosome analysis based on a Blood test beeing confirmed.
In addition, the internal organs, especially the heart be examined for malformations.

The diagnosis can also be made in the womb using Chromosome analysis respectively.There are various methods of doing this. Both amniotic fluid and samples of the placenta (placenta) can be removed. These samples are then examined genetically. There is also the possibility with one Prenatal testto examine the mother's blood for the child's genome and thus to discover changes before the birth with low risk. It should be noted that prenatal features in the fetus are not sufficient criteria for a diagnosis.

In principle, Down syndrome can be diagnosed at a very early stage if there is reasonable suspicion. This early diagnosis is through a Analysis of the embryonic genetic material possible. So in principle there is a diagnosis from the 10th week of pregnancy possible. However, the genetic material is either removed by invasive methods umbilical cord, the Amniotic fluid or the placenta won and therefore always goes with a certain Risk of miscarriage hand in hand.

Read more about the topic here Signs of a miscarriage

Newer methods, on the other hand, make it possible to filter out fragments of the embryonic genetic material from the mother's blood and analyze them. However, these methods are not yet fully established. But also a Ultrasonic As part of the Prenatal diagnostics can provide initial indications of trisomy 21. Above all a small head (Microcephaly), Heart defect or generally low growth are the most common signs here.

therapy

Nowadays the physical complaints such as Heart defect or a higher palate can be treated well with operations. Eventual Visual defects are using a glasses balanced. Furthermore, possibly occurring Speech disorders be treated by speech therapists.

To train the skills and to further support children with Down syndrome, there are further therapy options such as Occupational therapy, physiotherapy and also animal-assisted forms of therapy (e.g. therapeutic riding) are available.

prophylaxis

A prevention of Trisomy 21 / Down's disease is not possible, because 95% of the cases are not hereditary diseases, but a new combination occurs.

The chromosomes of the fetus can already be analyzed in the womb. So with a High risk pregnancy From the 35th year of life of the mother diagnose a possible trisomy 21.
The legislature allows one Termination of pregnancy / abortion to 12th week of pregnancy. Special regulations may apply to trisomy 21.

forecast

The medical supplies nowadays is very good. As a result, people with Down syndrome, who previously mostly did not survive puberty, can now live up to 60 years and older. For this purpose, possible severe malformations (for example heart defects) are identified and operated on at an early stage.

Summary

Down syndrome is based on a genome mutation.

Trisomy 21, also known as Down syndrome, is a maldistribution of parental chromosomes in your child. The sick person has three instead of two chromosomes of the number 21.
Trisomy 21 is the most common chromosomal aberration in newborns. Every 700th newborn in Germany is born with this syndrome. In rare cases (approx. 5%) there is inheritance.
As a rule, there are chromosomal new combinations. This probability of this increases with the age of the mother.
The physical characteristics of people with trisomy 21 may include a slightly wide nose, slanted eyes, low-set ears, a short neck, and a high palate, among others.
A so-called four-finger furrow often appears on the hands. Heart defects and other impairments of other internal organs are also possible in Down syndrome.
A reliable diagnosis of fetuses in the womb can only be made by means of chromosome analysis.
The life expectancy of a person with Down syndrome nowadays is around 60 years or older, since the organ malformations can be recognized and treated at an early stage.