Prenatal Diagnosis

PRENATAL DIAGNOSIS

Prenatal diagnosis is examining the samples including genes or chromosomes belonging to the foetus before birth. For prenatal diagnosis, samples belonging to the foetus are obtained by invasive methods.

Chorionic villus biopsy (CVS) is one of these methods and in this method, sampling is made from intra uterine face of placenta  in the 10th week of pregnancy for genetic examination.

Same examination could be made by another method called Amniocenteses (AS) in the 16th week of pregnancy. Amniocenteses (AS) is sampling from the liquid that contains the  foetus.

It is possible to perform another examination called Cordocenteses (CS) after the 20th week of pregnancy or if there are doubts about earlier examinations. Cordocenteses is sampling from foetus’ cordon blood and making genetic examinations on foetal blood.

CVS, AS or CS are performed by obstetricians and gynecologists and samples are tested in genetic diagnosis centers.

Indications of Prenatal Diagnosis are;

• Advanced maternal age, especially over 35
• NIPD result (risk doubles or triples on  test results obtained from maternal serum)
• Chromosomal abnormalities in previous birth (in this case, prenatal diagnosis is recommended in the latest pregnancy)
• Numeric and structural chromosomal abnormality carrier female or male parent (Sometimes both, normal and numeric chromosomal abnormality carrier cells can be seen in the same person. This case is called mosaicism. Prenatal diagnosis is made to prevent diseases such as Turner or Klinefelter syndrome because numeric differences can be seen in the baby according to mosaicism rate in mosaicism phenomenons in terms of sex chromosomes

(X and Y)

• The fact is that 50-60% of frequent miscarriages originate from chromosome abnormalities. Trisomias are responsible of half of this rates (50-60%). Most frequent trisomias are seen in 13rd, 16th, 18th, 21st chromosomes. For prenatal diagnosis, cytogenetics or FISH examination can be applied.
• The application of molecular genetics methods at prenatal diagnosis is highly important to prevent single-gene diseases As for the hereditary characteristic of the disease, single-gene diseases’ transmission possibility is between 25-50% from  female or male carrier parent. Both male and female parents should be tested if they are carriers, otherwise not to make a prenatal diagnosis of these conditions may usually cause severe problems.

For more detailed info about prenatal diagnosis processes and methods please visit www.gebelikvegenetik.com web site.

NESİLLER GENETİK PRENATAL DIAGNOSIS TESTS