Down Syndrome

What is Down Syndrome?

Every human cell contains 46 chromosomes, arranged in 23 pairs. In Down Syndrome, there is an extra chromosome, making 47 in total. Because there is an extra chromosome in the 21st pair, it is also called Trisomy 21. Down Syndrome is the most common chromosomal abnormality, occurring in about 1 in every 600–800 births. It causes intellectual disability and may lead to early death. Although not all cases can be detected, most can be diagnosed during pregnancy through various tests, allowing families to decide whether to continue or terminate the pregnancy.

Can Down Syndrome Be Detected Before Birth?

✔ Between the 11th and 16th weeks of pregnancy, triple screening tests (biochemical) and the 11–14 test (ultrasound measurement of nuchal translucency) are used to estimate the risk of Down Syndrome.

✔ These screenings indicate the probability but not a definitive result.

✔ A definite diagnosis is made through amniocentesis or chorionic villus biopsy.

✔ Since women over 35 have a higher risk of having a baby with Down Syndrome, diagnostic testing is recommended.

✔ Pregnant women found to be at risk through these screenings are advised to undergo amniocentesis or chorionic villus biopsy.

✔ Amniocentesis involves analyzing fluid taken during the 14–16th weeks of pregnancy, while chorionic villus biopsy examines a small sample from the placenta in early pregnancy.

Types of Down Syndrome

✔ About 95% of all cases are Free Trisomy 21, the most common type.

✔ Advanced maternal age and fathers over 50 increase the risk.

✔ The chromosome number is 47, and all signs of Down Syndrome are present.

✔ Around 4–5% of cases are Translocation Trisomy 21.

✔ The chromosome number remains 46, but the extra chromosome attaches to another one.

✔ Family chromosome analysis is recommended because 25% may carry a translocation.

✔ All symptoms of Down Syndrome are also found in Translocation Trisomy 21.

✔ Another type is Mosaic Trisomy 21.

✔ It occurs when an error happens in one cell during division.

✔ Some cells have 46, others 47 chromosomes.

✔ It makes up 1–2% of all cases.

✔ The severity varies depending on which cells are affected.

How Is Down Syndrome Recognized in a Child?

✔ Typical features of children with Down Syndrome include:

✔ Round face, flat nasal bridge.
✔ Slightly slanted eyes.
✔ Flat neck and possible skin fold.
✔ Low muscle tone at birth.
✔ Small mouth and protruding tongue due to muscle weakness.
✔ Broad hands, short fingers.
✔ Narrow feet with a gap between the first and second toes.
✔ Normal birth weight and height but shorter stature as they grow.

What Is the Risk for a Second Child?

✔ In Trisomy 21, recurrence risk is below 1%.
✔ In Translocation Trisomy 21, if it occurs newly, there is no recurrence risk.
✔ If inherited from parents, the risk is 8–10%.
✔ In Mosaic Trisomy 21, risk is low but possible.

What Should Be Done if the Child Has Down Syndrome?

✔ The social environment plays a vital role in the child’s development.
✔ With proper education, they can overcome many difficulties.
✔ They can learn a profession and lead an independent life.
✔ They should be encouraged to be socially active.
✔ Physical therapy, special education, and speech therapy are needed.

Treatment of Down Syndrome

✔ Down Syndrome is not contagious or hereditary; it is a genetic difference like eye or hair color.
✔ There is no surgery or medication for the extra chromosome.
✔ Problems caused by Down Syndrome can be managed with supportive therapies such as physical therapy, special education, and speech therapy.

Special Education

✔ Individualized programs must be prepared for each child.
✔ Family support is essential alongside professionals.
✔ Education should promote emotional, cognitive, and motor development.

Physical Therapy

✔ Early physical therapy greatly supports motor development.
✔ It helps with feeding difficulties due to weak facial muscles.
✔ Separate programs target facial and tongue muscle development.
✔ Muscle strength and motor skills are supported.

Speech Therapy

✔ Speech develops late in children with Down Syndrome.
✔ Hearing issues must be addressed.
✔ Early quality speech therapy may enable speech by age 2–3.