Down's Syndrome

Overview

Down's syndrome is a congenital chromosomal anomaly, consisting in the presence of an extra chromosome in the 21st pair (trisomy of the 21st pair of chromosomes). A person has 23 pairs of chromosomes, so an ordinary child has 46 chromosomes, and a child with Down syndrome has 47. Down syndrome is characterized by a special appearance of the patient and a decrease in intellectual abilities. The frequency of this chromosomal anomaly in the population is 1:800 and does not depend on gender, race, family standard of living, or the presence or absence of bad habits in parents.

Types:

There are three types of Down syndrome:


1. Trisomy 21. 
Chromosome 21 is present in three copies rather than two in each cell of the body in the most prevalent kind.

2. Translocation form of Down syndrome. 
In this case, each cell has part or all of the entire 21st chromosome. Only it is attached to another chromosome.

3. Mosaic shape. 
This is the rarest type, when an additional 21st chromosome is present only in some cells.

It is impossible to determine the type of syndrome by appearance.

The effects of all three types are very similar, and yet in the case of the mosaic form, the symptoms are less pronounced, because the extra chromosome is not found in all cells.



Symptoms

Physiological symptoms:
In fact, they are different, but certain physical traits are common in most patients with a chromosomal abnormality.

Face:

1. Almond-shaped eyes (the shape may be uncharacteristic of the ethnic group);

2. Flat face, flattened nose;

3. Small ears that curl a little at the tips;

4. Tiny white spots on the iris;

5. The tip of the tongue protruding from the mouth.


Small arms and legs with characteristic features:
1.     A single transverse crease in the palm;
2.    Short fingers;
3.    Small little fingers that curl towards the thumbs.
Also observed:
-    Low muscle tone;
-    Loose joints, making them very flexible;
-    Low growth in both children and adults;
-    Short neck;
-    Small head.
At birth, children with Down syndrome rarely differ in size from other newborns, but later grow more slowly. Because they often have poor muscle tone, babies may appear lethargic and raise their heads late, although this is temporary. Low muscle tone can also affect the sucking reflex and feeding, which ultimately affects weight



Causes

Each of the cells in our body has 23 pairs of chromosomes. One chromosome from the mother and one from the father are present in every pair of chromosomes.
A failure happens in this instance, though, and a second copy of the 21st chromosome is found in the body. Doctors have a hard time pinpointing the precise cause of this. The surroundings, the parents' health, or their way of life have no impact on the emergence of new genetic material.
And while doctors don't know what exactly causes the genetic fault, they have managed to find out that women 35 and older are more likely to have a baby with Down syndrome. Also, the likelihood increases if you previously had a newborn with this pathology.
 



Prevention

Since each couple has a chance of having a sick kid, the only way we can discuss preventing Down syndrome is by lowering potential risks. Obstetricians and gynaecologists counsel women against waiting till a later age to get pregnant. The system of prenatal screening and genetic counselling for families are meant to benefit from the ability to predict the birth of a child with Down syndrome.
 



Tests Required for Diagnosis

Prenatal:
There are two categories of tests for chromosomal abnormalities that can be performed before delivery: screening (non-invasive) and diagnostic (invasive). Prenatal screenings assess the risk of developing a pathology in the fetus, and diagnostic screenings make a diagnosis.

Today, there are many prenatal screening tests available for pregnant women. The most common are biochemical blood tests and ultrasound. A blood test measures the amount of various substances in the mother's blood. Together with a woman's age, it is used to assess the chances of having a child with Down syndrome. This analysis is often done in conjunction with an ultrasound scan for markers (characteristics that may indicate pathology).
Unfortunately, these methods often give false positive and false negative results.

New prenatal screenings detect fetal DNA circulating in the mother's blood. These tests are non-invasive, that is, they do not pose a threat to the fetus, but at the same time they provide higher accuracy than biochemistry and ultrasound - up to 99%.

Diagnostic procedures for prenatal diagnosis of the syndrome include chorionic biopsy and amniocentesis. The associated probability of spontaneous abortion is up to 1%. Moreover, such tests are almost 100% accurate in the diagnosis of Down syndrome. Amniocentesis is usually performed in the second trimester between 15 and 20 weeks of gestation, chorion biopsy in the first trimester between 9 and 14 weeks.

At Birth:
The syndrome at birth is usually identified by the presence of certain external and physical signs: low muscle tone, a single transverse palm crease, a slightly flattened facial profile, and almond-shaped eyes with a distinct epicanthus.
But since all these signs can be present in children without Down syndrome, a chromosomal analysis called karyotyping is performed to confirm the diagnosis.
To perform karyotyping, doctors take a sample of a newborn's blood to examine its cells, analyze chromosomes, and group them by size, number, and shape.


Medical and pedagogical support for children with Down syndrome

Cure of chromosomal anomaly is currently impossible; any proposed treatments are experimental and have no proven clinical efficacy. However, systematic medical supervision and pedagogical assistance to children with Down syndrome make it possible to achieve success in their development, socialization and the acquisition of labor skills.

Throughout life, patients with Down syndrome should be under the supervision of specialists due to concomitant diseases or an increased risk of their development. If severe congenital malformations of the heart and gastrointestinal tract are detected, their early surgical correction is indicated. In case of severe hearing loss, a hearing aid is selected. In case of pathology of the organ of vision, spectacle correction , surgical treatment of cataracts may be required, glaucoma, strabismus. In case of hypothyroidism, thyroid hormone replacement therapy is prescribed, etc.

    
To stimulate the development of motor skills, physiotherapy and exercise therapy are indicated. For the development of speech and communication skills, children with Down syndrome patients need classes with a speech therapist.
 



Useful info

Mental Status:
The syndrome affects the thought process and socialization, in which case the effects range from mild to moderate. Babies often take longer to learn to crawl, walk and talk. They later begin to dress themselves and go to the toilet on their own. And at school, they may need help learning to read and write.
Some children with this chromosomal abnormality have behavioural problems such as attention deficit or obsession. This is because they find it harder to control their impulses, communicate with other people, and manage their emotions when they are upset.
As adults, people with Down syndrome learn to do many things on their own, but they are more likely to need help with more complex matters, such as birth control or financial management.

Health status:
1. Hearing loss. Many people have unilateral or bilateral hearing problems.
2. Heart failure. About half of all children with congenital disorders have heart problems.
3. Obstructive sleep apnea. This treatable condition is characterized by repeated pauses in breathing during sleep.
4. Vision problems. About half of people with trisomy 21 have vision problems.


With a high probability they have the following pathologies:

- Anemia - a blood iron level that is lower than normal.
- Leukaemia - a type of blood cancer.
- Dementia associated with memory loss and mental decline. Signs and symptoms often begin around age 50.
- Infections. People with trisomy 21 tend to get sick more often because they tend to have weaker immune systems.

Such people are also more likely to be overweight and have thyroid problems, frequent blockages in the digestive tract and skin problems.


Is Down syndrome inherited?
Genetic circumstances underlie each of the three kinds. There is no inheritance in trisomy 21 or mosaicism. Only one third of translocation-related cases of Down syndrome have a hereditary component; these cases make up about 1% of all cases of the syndrome.

Age of the mother doesn't seem to affect the likelihood of a translocation. These are typically unplanned events. One of the parents is the carrier of the translocated chromosome in around one-third of instances, though.

What is the probability of having a second baby with Down syndrome in the same family?

By the time she reaches the age of 40, a woman is considered to have a one-in-100 chance of having another child with trisomy 21 after having one with a translocation.
If the father is the carrier, there is a 3% chance of the translocation happening again, and if the mother is, there is a 10-15% possibility. Finding the translocation's origin will be made easier with the aid of a genetics consultation.


Risk Factors:
1. Mother's age 35+. The chances of giving birth to a child with trisomy 21 increase with age: the older the egg, the higher the likelihood of abnormal chromosome division. The risk of conceiving a child with the syndrome for a woman increases after 35 years. And although most of these children are born to women under the age of 35, this is due only to the fact that young people, in principle, give birth more often.

2. Carrying a translocation. Both men and women can pass on the translocation form of the syndrome to their children.

3. Previously born baby with the syndrome. Parents who already have one kid with trisomy, as well as those who have a translocation, are more at risk. An expert in genetic counselling can help parents assess the possibility of having a second child with Down syndrome.

Complications:

Heart disease. About half of newborns are born with some form of congenital heart disease. This condition can be life-threatening; likely to require surgery in infancy.

Defects in the gastrointestinal tract. Gastrointestinal tract abnormalities occur in some patients, including malformations of the intestine, esophagus, trachea, and anus. Increased risk of developing digestive problems - blockage of the gastrointestinal tract, heartburn and celiac disease.

Immune disorders. Due to malfunctions in the immune system, people with the syndrome are at an increased risk of developing autoimmune disorders, certain forms of cancer, and infectious diseases such as pneumonia.

Apnea. Because of soft tissue and skeletal changes that lead to airway obstruction, children and adults with Down syndrome are at greater risk of developing obstructive sleep apnea.

Obesity. Individuals with the syndrome show a greater tendency to become obese than the general population.
Spinal problems . Some people with Down syndrome may have a misalignment of the top two vertebrae in their neck. This condition creates a threat of serious spinal cord injury from neck strain.

Leukemia. "Sunny" children have an increased risk of developing leukemia.

Dementia. People with trisomy 21 are more likely to develop dementia; signs and symptoms may begin around the age of 50. The presence of congenital pathology also increases the risk of developing Alzheimer's disease.

Other problems. Endocrine diseases, dental issues, seizures, ear infections, and issues with hearing and vision are just a few of the various ailments that have been linked to down syndrome.
People with the syndrome can maintain a healthy lifestyle by receiving regular medical care and attention.

Lifespan:
The life expectancy of people with Down syndrome has increased significantly in recent years. Today, one can live with this condition for more than 60 years, but this, of course, depends on the severity of health problems.

 



Disclaimer

The information provided in this article is for general informational purposes only. It is not intended as a substitute for professional medical advice, diagnosis or treatment. For any concerns about your health or you are experiencing symptoms, it is important to consult with a healthcare professional. They will be able to assess your specific situation and provide you with personalised advice and treatment based on your symptoms, body type, allergies (if any), existing medical conditions etc. It is always better to consult with a healthcare professional before making any decisions about your health. By accessing this article you agree with our terms and condition https://proceed.fit/frontend/terms_conditions.