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Down's syndrome What we need to know


Down's syndrome is associated with the presence of an extra chromosome in the 21st pair of chromosomes.

A normal person has 46 chromosomes, but a child with Down's syndrome has 47. This leads to a violation of the child's physical and mental development. It is a natural human condition that is a syndrome, not a disease. A syndrome, i.e., a combination of symptoms that have a common cause.

It is possible to have a child with Down's syndrome at an earlier age, however, the chances of having a child with Down's syndrome increase as a woman ages. One in every 700-900 babies may have Down syndrome. There is no exact reason why chromosomes divide incorrectly. This happens by chance during conception (when the egg is fertilized by the sperm).

Physical signs characteristic of Down syndrome are:

  •  Flat facial profile - 90%
  •  Brachycephaly - flattened occipital bone - 81%
  •  Skin folds on the neck in newborns - 81%
  •  Epicanthus - a small skin fold in the inner corner of the eyes - 80%
  •  There are pigment spots on the edges of the colored membrane of the cloth
  •  Low muscle tone - hypotonia - 80%
  •  straight back -78%
  •  small limbs-70%
  •  Brachymesophalangeal - the small size of the fingers, which is related to the incomplete development of the surrounding phalanges - 70%
  •  An open mouth, which is associated with low tone of the muscles responsible for facial expressions and a special structure of the palate - 65%
  •  Clinodactylosis, presence of one instead of two flexor joints on the 5th finger - 60%
  •  Large tongue compared to the size of the person - 50%
  •  Short neck with wrinkled skin -50%
  •  Flat nasal septum - 40%
  • Low-lying ear canals with characteristic folds.

Diseases associated with Down syndrome include:

  •  congenital heart disease;
  •  childhood leukemia;
  •  vision and hearing problems;
  •  Digestive problems.

There are several forms of Down syndrome:

  •  Trisomy 21 is the most common form and occurs in 95% of cases.
  • Translocation, which occurs in 3-4% of cases.
  •  Mosaicism, which is very rare and occurs in 1-2%. At this time, some cells contain 47 chromosomes, and some contain the normal number of chromosomes - 46.


There are two main types of tests available to prevent fetal syndromes during pregnancy (prenatal period): screening tests and diagnostic tests. Screening and diagnostic tests determine whether a fetus has a low or high chance of developing various syndromes.

If the screening tests show that you have a high risk of having a baby with Down syndrome, it is recommended that you also have a diagnostic test to determine if the fetus has a genetic disorder.

  1. Screening tests – A prenatal screening test can determine if your baby is more or less likely to have birth defects, many of which are genetic disorders. These tests include blood tests, specific ultrasounds, and prenatal cell-free DNA screening.
  2. Diagnostic tests – After the screening test, the final answer is given by a diagnostic test that examines the genetic material of the fetus and can therefore determine whether the fetus has a genetic disorder. Invasive and non-invasive prenatal diagnostic tests ((NIPT) Verasiti, Veragen) It is the only, safe and effective way to confirm the diagnostics. Be aware that some diagnostic tests, such as chorionic villus sampling and amniocentesis, carry a small risk of miscarriage.

Learn more about prenatal diagnostics → ( 


Down syndrome is a lifelong condition. Early childhood mental and physical development programs often help children with Down syndrome improve their physical and intellectual abilities.

Most of these services are focused on developing children with Down syndrome to their full potential. Early intervention programs include speech therapy and occupational physical therapy. Children with Down syndrome may also need extra help or attention at school.





For prenatal screening of Down's syndrome, "Synevo" laboratory offers the following tests:

Name of the test Category Price CODE Response time (working day) ** Location of the analysis **** Buyhf: categories

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