Down Syndrome

Feb 08, 2024

Table of contents

What is Down syndrome?

As a result of abnormal cell division 21. It is a genetic disorder that occurs when a complete or partial copy of a chromosome occurs. This extra material from cell division causes the developmental changes and physical characteristics seen in Down syndrome.

Although the severity of Down syndrome varies between individuals, it causes mental disabilities and developmental delay. It is the most common genetic disorder and cause of learning disabilities in the pediatric population. It also causes different medical abnormalities such as heart, stomach and intestinal diseases. Understanding Down syndrome and early interventions can significantly improve the quality of life of individuals.

Down syndrome diagnostic criteria

Down syndrome can be diagnosed in the womb or after birth. Diagnostic and screening tests are recommended to detect Down syndrome in the womb.

Screening tests during pregnancy

Screening for Down syndrome is one of the routine tests performed during pregnancy. Screening tests can help determine the risk of having a baby with Down syndrome. However, specific diagnostic tests can provide a definitive result. Screening tests include the first trimester combined test and the integrated screening test.

First trimester combined test

The first trimester combined test is performed in two steps. These tests include.

  • The blood test measures plasma levels of pregnancy-associated protein A and the pregnancy hormone known as human chorionic gonadotropin. Normal levels of these hormones can be taken as an indication that the baby may have an abnormality.
  • The nuchal translucency test measures a specific area on the back of the baby's neck. Ultrasound imaging is used for this procedure. The presence of abnormalities in this test, also known as the nuchal translucency screening test, is considered an indication that there is more fluid accumulation in the neck than there should be.

Integrated screening test

Integrated screening tests are performed in both the first and second trimesters of midwifery. Both tests are evaluated together to determine the baby's risk of Down syndrome.

  • The tests performed in the first trimester are a blood test and a nuchal translucency test.
  • The second trimester quad screening test determines the levels of four substances that are associated with pregnancy. These substances are alpha fetoprotein, estriol, HCG and inhibin A.

Diagnostic tests during pregnancy

If the results of screening tests are positive or alarming, further tests are required to establish a definitive diagnosis. The pros and cons of these tests should be discussed with the doctor. Among the tests that are carried out to ensure that the risk of Down syndrome is fully diagnosed are the following.

Chorionic villus sampling

In this test, also called CVS, cell samples are taken from the placenta. The samples are then used to analyze the chromosomes. The CVS test is usually performed between the 10th and 13th days of pregnancy. It is held during the week. Miscarriage due to CVS is unlikely to occur.


In this test, a needle is inserted into the mother's uterus and samples are collected from the amniotic fluid surrounding the baby. These samples allow the fetal chromosome number to be analyzed. This test is usually performed on the 15th day of pregnancy. week and the risk of miscarriage is low.


It is a test for couples undergoing IVF treatment who are at high risk of passing on certain genetic conditions. In this test, the embryo is tested for genetic abnormalities before implantation.

Screening test for newborns

After birth, Down syndrome is usually diagnosed based on the baby's appearance. However, since the features associated with Down syndrome can be seen in babies without Down syndrome, a test called a chromosomal karyotype is required to confirm the diagnosis.

Causes of Down syndrome

Under normal conditions, human cells contain 23 pairs of chromosomes. One chromosome in each pair comes from the mother and the other from the father. The occurrence of Down's syndrome can be traced back to the 21st century. occurs in the case of abnormal cell division on a chromosome. This genetic condition manifests itself in three different ways.

Down syndrome is usually not a genetically inherited condition. It is caused by an abnormality in cell division during early fetal development. However, in individuals with translocated Down syndrome, the condition can be passed on to the child.

Down syndrome symptoms

Developmental and intellectual symptoms in individuals with Down syndrome can vary from mild to moderate to severe. Some patients may have serious health problems such as heart problems.

Facial features differ in individuals with Down syndrome. Although not all individuals have the same characteristics, there are common features. These common features include the following.

  • Flattened face
  • Short neck
  • Upward-slanted eyelids
  • Poor muscle tone
  • Wide and short hands with a single curve in the palm
  • Excessive flexibility
  • Short length
  • Small head
  • Protruding tongue
  • Unusually shaped or small ears
  • Relatively short fingers and toes
  • Small white spots in the iris of the eye called Brushfield spots
  • Babies may be of average size, but they usually grow slowly and are shorter than children of the same age.

Children with Down syndrome can have intellectual and developmental disabilities. It is therefore possible that the child's ability to meet developmental milestones may vary. These changes include the following.

  • Development of gross and fine motor skills
  • Language skills
  • Cognitive skills
  • Social and emotional skills

Because of these changes, children with Down syndrome may have the following conditions for longer.

  • Toilet training
  • Beginning to say their first words
  • First steps
  • Eating food independently

Down syndrome also has an impact on children's behavior. Behavioral symptoms that may occur in children with Down syndrome include the following.

Down syndrome risk factors

Some parents are more likely to have a baby with Down syndrome. These risk factors include the following.

Advancing age of the mother

The risk of having a child with Down syndrome increases with age. This is because older eggs have an increased risk of faulty chromosome division. This risk is especially high if you become pregnant after the age of 35.

Being carriers of the genetic translocation for Down syndrome

The genetic translocation of Down syndrome in both men and women can be passed on to children.

Having a child with Down syndrome

Parents who have a child with Down syndrome are more likely to have other children with Down syndrome. To prevent this, a genetic counselor can be consulted during pregnancy planning.

Complications of Down syndrome

There are some complications that can occur in people with Down syndrome. Some of these complications are exacerbated by advancing age. Complications that can be seen in Down syndrome include the following.

Heart defects

Approximately half of people with Down syndrome have congenital heart defects. Some of these problems can be life-threatening. For this reason, surgery may be necessary in infancy.

Gastrointestinal (GI) defects

Individuals with Down syndrome may also have digestive system problems. These problems affect the intestine, esophagus, trachea and anus. In addition, problems such as GI obstruction, celiac disease and reflux can also be seen.

Immune disorders

Autoimmune disorders caused by immune abnormalities in individuals with Down syndrome put them at higher risk of developing certain types of cancer and infectious diseases such as pneumonia.

Sleep apnea

The genetic changes seen in Down syndrome can cause sleep apnea due to soft tissue and skeletal changes that cause obstruction of the airways.


Individuals with Down syndrome are more prone to obesity than the normal population.

Spine problems

Some people with Down syndrome may have misalignment of the upper two vertebrae in the neck. This causes serious injury to the spinal cord due to the excessive lengthening of the neck of individuals.


Children with Down syndrome are more likely to develop leukemia than the general population.


People with Down syndrome can develop dementia symptoms after the age of 50. Down syndrome also increases the risk of Alzheimer's disease.

Other problems

Other complications that can occur in people with Down syndrome include

  • Endocrine problems
  • Dental problems
  • Seizures
  • Ear infections
  • Hearing and vision problems

Down syndrome treatment

The treatment of Down syndrome requires a team to provide medical care. In this way, their skills can be developed as much as possible, while at the same time possible complications can be treated. It is also possible to expand the medical team according to the specific needs of the child.

  • Primary care pediatrician to coordinate routine care
  • Pediatric cardiologist
  • Pediatric gastroenterologist
  • Pediatric endocrinologist
  • Developmental pediatrician
  • Pediatric neurologist
  • Pediatric otolaryngologist
  • Pediatric ophthalmologist
  • Audiologist
  • Speech pathologist
  • Physiotherapist
  • Occupational therapist

Parents need to make important decisions about the education and treatment of children with Down syndrome. It is therefore extremely important for the family to form a group of trusted teachers and doctors.

While there is no cure for Down syndrome, it is important to make appropriate use of support to help the child realize his or her potential. These treatments support the child's physical and cognitive development. Treatment options for Down syndrome include the following.

  • Physical and occupational therapy
  • Speech therapy
  • Participating in special education programs in schools
  • Treatment of diseases caused by Down syndrome
  • Use of glasses or hearing aids to correct vision or hearing problems

Down syndrome symptoms during pregnancy

Symptoms of Down syndrome during pregnancy do not affect the mother. However, a high fetal width on ultrasound monitoring is considered to be an indication of the risk of Down syndrome. Otherwise, the expectant mother will have a normal pregnancy and the fetus will continue to develop normally.

Down syndrome causes of death

Heart and lung problems are the leading causes of death in people with Down syndrome. Pneumonia and other infectious lung diseases, congenital heart defects (CHD) and circulatory disease (vascular disease not including CHD and involuntary heart disease) account for 75% of the causes of death in people with Down syndrome. In addition, involuntary cardiovascular disease, which causes death in 30% of the normal population, affects 7% of individuals with Down syndrome.

How many years does Down syndrome live?

The life expectancy of people with Down syndrome has improved dramatically. As a result of these developments, individuals with Down syndrome live for more than 60 years, depending on the severity of their health problems.

Types of Down syndrome

Down syndrome 21. due to a defect in the chromosome. This error occurs in different ways. Down syndrome is therefore diversified.

Trisomy 21

It occurs in approximately 95% of people with Down syndrome. In this type, all cells of the individual have 21 instead of the normal two copies. There are three copies of a chromosome. This is caused by abnormal cell division during the development of the sperm or egg cell.

Translocation Down syndrome

Translocation 21 in Down syndrome. Part of a chromosome is attached to another chromosome during or before fertilization. In these individuals 21. There are two copies of a chromosome. On the other hand, it is linked to another chromosome 21. They also have additional material from the chromosome.

Mosaic Down syndrome

Only some cells of people with mosaic Down syndrome, a rare form of Down syndrome, have 21. there is an extra copy of the chromosome. This mosaic of both normal and abnormal cells is caused by abnormal cell division after fertilization of the sperm and ovary.

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