Contents
In line with its mission, the Editorial Board of MedTvoiLokony makes every effort to provide reliable medical content supported by the latest scientific knowledge. The additional flag “Checked Content” indicates that the article has been reviewed by or written directly by a physician. This two-step verification: a medical journalist and a doctor allows us to provide the highest quality content in line with current medical knowledge.
Our commitment in this area has been appreciated, among others, by by the Association of Journalists for Health, which awarded the Editorial Board of MedTvoiLokony with the honorary title of the Great Educator.
Down syndrome is a group of birth defects caused by an abnormal number of chromosomes. Characterized by, inter alia, mild or moderate intellectual disability and features of dysmorphia, i.e. changes in appearance. In addition, in the course of the disease, there are a number of disorders in the structure and functioning of the body. People with Down’s syndrome have distinctive folds above the eyelids that make them easy to recognize. The disease owes its name to its discoverer – doctor John Langdon Down identified it in 1862.
Down syndrome – causes
Down syndrome is a trisomy of the 21st pair of chromosomes. This means that the 21st pair has an extra third chromosome or a fragment of it.
Down syndrome is a fairly common genetic disease with a frequency ranging from 1: 800 to 1: 1000 live births.
To date, no physical factors that increase the risk of Down’s syndrome have been identified. However, a correlation was found between the age of the mother and the probability of having a child with a trisomy of the 21st couple. It is worth mentioning that in women in their 30s, the risk of having a baby with Down’s syndrome is almost twice as high as in women in their 20s.
Professional medical care is very important during pregnancy. Therefore, women should consider purchasing a medical subscription for pregnant women for this special period, which allows them to take advantage of many consultations without a referral.
The incidence of Down’s syndrome is on average 1: 600 births.
In the 1:80 prenatal period, as not all babies will survive, we often see stillborn pregnancies or spontaneous abortions. It is reported that every seventh child with trisomy 21 survives to delivery.
Down syndrome can affect both male and female genders. 21st chromosome failure can occur in both paternal and maternal cells. Damage, however, occurs more often in mother’s cells, as they mature longer than father’s cells, and are therefore more exposed to harmful factors.
Down syndrome is about 10 times more common in newborns born to mothers over 40 years of age, and it is not affected by whether or not they had a baby before. This does not mean, however, that young mothers do not have a chance to give birth to sick offspring.
Some believe that in the body of a young woman / mother it is much more likely to recognize changes in a fetus with an extra chromosome 21. It then leads to a spontaneous miscarriage. The fact is that 10% of all pregnancies of women of childbearing age undergo spontaneous abortions and a significant proportion of them contain various chromosomal aberrations, including an extra 21 chromosome.
Any doubts related to the risk of trisomy 21 should be consulted with a gynecologist as soon as possible. That is why we recommend comfortable and safe gynecological consultations without leaving home.
Down syndrome – symptoms
Most people associate Down’s syndrome with mental retardation and a distinctive appearance, but these are only some of the symptoms we see in people with Down’s syndrome. All patients also have hereditary immunodeficiency, which significantly increases the frequency of various types of infections. Patients also show flaccid muscles, which means that they often do not close their mouths and stick out their tongues.
Other conditions can also appear in Down’s syndrome. Some of them are only dysmorphic features that do not deteriorate the quality of life, but there are also serious disadvantages. Patients may develop: heart defects, hearing disorders, short head, tooth hypoplasia, cataracts and other eye disorders, defects in the digestive system, celiac disease, skeletal abnormalities, changes in the genitourinary system, fertility disorders, thyroid disorders, epileptic seizures and many others.
Leukemia is also common in people with Down’s syndrome, but interestingly enough, patients have a much lower incidence of other malignancies.
The average life expectancy of people with Down syndrome is currently 49 years. Usually, death occurs as a result of serious heart defects.
External symptoms suggestive of Down’s syndrome
The external features of Down’s syndrome are most visible on the face:
- the eyelids are slanting upwards;
- angular wrinkles;
- short bridge of nose;
- bright spots on the iris of the eye;
- small hypoplastic turbinates of the ears;
- narrowed external auditory canal;
- short hands;
- large space between the big toe and the other toe (both sides);
- sandal furrow on the sole;
- the course of the main line on the hands in a transverse manner.
There are many features of this kind, but they are not common to everyone with Down’s syndrome. At least ten features are needed to perform a karyotype test. This test is the most reliable method needed to diagnose Down’s syndrome, because the above-mentioned features may also appear in people who do not have an extra 21 chromosome.
Types of Down syndrome
There are three types of Down syndrome from the point of view of cytogenetic diagnosis.
1. Simple chromosome 21 trisomy – all cells in the body contain an extra 21 chromosome.
2. Trisomia 21 mozaikowa – in this case, only some of the cells in the body contain an extra 21 chromosome, and the rest have a normal karyotype.
3. Translocation 21 trisomy – chromosome 21 is linked to another chromosome.
Down syndrome – treatment
Down’s syndrome is incurable. Often it is necessary to use treatments to eliminate the symptoms of the disease – for example, surgical correction of heart defects. In addition, therapies are used to improve the quality of life of patients.
Down syndrome is the natural biological variability of humans that no one is to blame. In fact, it is not possible for a person to predict whether his child will be born with Down syndrome, and there is no way to prevent the failure of the 21st chromosomes to separate in the maternal or paternal cell.
The development of Down’s syndrome is not affected by any diseases that occur in the father or mother. The extra chromosome 21 is made mainly in the parents’ germ cells or early in the development of a child. If we perform a parental karyotype test, it is usually correct.
Therefore, we say that Down syndrome is a genetic difference (it has an altered karyotype), but the change was not inherited from the parents. Down syndrome inheritance occurs very rarely, in order to determine the genetic predisposition, the karyotype should be tested and its forms determined, and then the parents should be tested.
If there is no significant mental impairment, and hence – incapacitation – people with Down syndrome may marry. Despite the decline in fertility, it happens that these couples have children, but rarely consciously decide to have offspring because of the high risk of passing on a genetic defect (35-50% when one of the parents is sick).
Professional literature reports that 2/3 of children born to women with Down syndrome are healthy. Men with Down syndrome are usually sterile.
Down syndrome and life expectancy
A child with Down’s syndrome, just like healthy children, has certain characteristics inherited from their parents, grandparents or other ancestors. The presence of an extra 21 chromosome transforms the natural interplay between genes, environment and genes – this affects life expectancy. Thanks to better perception of people with Down syndrome by the environment, their life expectancy and quality of life have improved, as opposed to patients who are isolated from society. Life expectancy also depends on the malformations that may accompany the disease: digestive system diseases, heart defects or hypertension.