Trisomy 21 Screening in Turkey: Down Syndrome Tests & Costs

What is exactly trisomy 21?

Trisomy 21, better known as Down syndrome, is a genetic condition caused by an extra copy of chromosome 21. Most people have 46 chromosomes; someone with trisomy 21 has 47.

That extra chromosome affects physical and cognitive development, often producing recognizable facial features and some degree of intellectual disability. But here's what's easy to forget: no two people with Down syndrome are the same. The condition varies widely from one individual to the next.

What causes this chromosomal abnormality?

Trisomy 21 happens when chromosome 21 fails to separate correctly during meiosis, the cell division process that forms eggs and sperm. Most often, this error originates on the maternal side, and it becomes more likely as the mother's eggs age.

A few things worth knowing:

• Maternal age is the leading risk factor, but not the only one; other genetic or environmental factors can play a role too.
• Trisomy 21 is not hereditary. It isn't passed down through families; it occurs spontaneously in the vast majority of cases.
• Only a fetal karyotype (a chromosomal analysis) can confirm the diagnosis. Screening only estimates risk.

Who should consider prenatal screening?

Doctors generally recommend trisomy 21 screening for any pregnant woman, but it's especially relevant if:

• You're past 11 weeks of pregnancy.
• You're 35 or older.
• There's a family history of chromosomal abnormalities.
• A routine ultrasound showed something worth investigating further.
• You simply want an early risk assessment without invasive testing.

At the end of the day, it's a personal decision, one best made after a clear, judgment-free conversation with your doctor.

How does trisomy 21 screening work in Turkey?

Turkish clinics partner with Turquie Santé, follow international protocols, and testing typically happens in stages.

First trimester (weeks 11–14):

• Nuchal translucency ultrasound: measures fluid at the back of the baby's neck; unusual thickening can signal a higher risk.
• Maternal blood test: checks biochemical markers linked to trisomy 21.
• Maternal age: factored in alongside the two results above to calculate an individualized risk score.

Second trimester (weeks 15–22): A second blood draw can re-evaluate the risk using additional biological markers, refining the picture from the first-trimester results.

Non-invasive prenatal testing (NIPT): This is the most sensitive option, analyzing fetal DNA that circulates in the mother's bloodstream. Istanbul's leading clinics offer it as early as the first weeks of pregnancy. It's remarkably accurate, but not infallible; false positives or inconclusive results do happen occasionally. If NIPT comes back positive, a diagnostic test (amniocentesis or chorionic villus sampling) is still needed to confirm anything.

How reliable is trisomy 21 screening, really?

Every screening test has a margin of error; that's true even for the most advanced options.

Only diagnostic procedures, amniocentesis or chorionic villus sampling, can confirm a chromosomal abnormality with certainty.

What do your results actually mean?

Your doctor will walk you through the results personally. Remember: this is a risk estimate, not a verdict.

• A "high risk" result doesn't mean your baby has Down syndrome; plenty of babies flagged as high-risk turn out perfectly healthy.
• A "low risk" result doesn't guarantee the absence of trisomy 21 either.

If your result comes back concerning or more precise, though more invasive, diagnostic testing may be suggested next.

What happens If the result shows elevated risk?

This is the part many patients want more detail on, so here's what typically follows an abnormal result:

• A specialist consultation to walk through exactly what the numbers mean for your specific case.
• A clear explanation of next steps, including which diagnostic test (amniocentesis or trophoblast biopsy) applies to your situation and when it can be done.
• The option, never the obligation, to pursue diagnostic confirmation.
• Emotional and medical support throughout the decision-making process, including access to parent groups who've navigated a Down syndrome diagnosis or parents who made a different choice.

You're never rushed into anything. The goal is to give you accurate information early enough that whatever you decide, it's genuinely your decision.