It is Possible to Diagnose Chromosomal Disorder with Genetic Tests

Genetic Diseases Evaluation Specialist Prof. Dr. İlhan Sezgin said that it is possible to diagnose chromosomal disorders with genetic tests.
Today, chromosomal anomalies such as Down syndrome can be diagnosed before birth with new advanced methods and screening tests. While correct selection and follow-up of screening and diagnostic tests performed during pregnancy is of great importance, Medicana Bursa Hospital Genetic Diseases Evaluation Specialist Prof. stated that family members should be aware before and from the beginning of pregnancy and even receive genetic counseling. Dr. İlhan Sezgin said that results can be obtained in an average of 7 days with genetic screening tests in the diagnosis of prenatal chromosomal disorders.Stating that prenatal genetic screening tests are performed by invasive and non-invasive methods, Prof. Dr. İlhan Sezgin gave the following information about these methods:
"Interventional methods are referred to as amniocentesis, chorionic villus sampling (CVS), cordocentesis, and preimplantation, while non-invasive methods include maternal serum alpha-fetoprotein, first and second trimester maternal serum screening, ultrasound, isolation of fetal cells from maternal blood and extracellular free radicals." These are the test methods used as fetal DNA studies (cffDNA or NIPT). Pregnancy over 35 years of age, abnormal maternal serum screening result, fetal anomalies detected by ultrasound, chromosomal anomaly in the previous child, child with learning disability in the family, parent with balanced chromosomal anomaly, biochemical or "In cases of family history of a genetic disease that can be determined by DNA analysis, neural tube defect (NTD) risk, family history of X-chromosome-related disease, screening can be performed for prenatal diagnosis."Prof. stated that screening is carried out at the 15th and 16th weeks of pregnancy for chromosomal disorders, biochemical screening and DNA analysis through amniocentesis. Dr. Sezgin said, "These tests can also be performed in the 10th-14th weeks. Especially for autosomal chromosomal tests, screening tests performed from the mother's serum reveal the chromosomes in terms of trisomy-21 (Down syndrome), trisomy-13 (Patau syndrome), trisomy-18 (Edwards syndrome). It is a necessary indication for analysis. It is an ideal approach to perform these screening tests between the 11th and 13th weeks of the first trimester. Today, for non-invasive prenatal diagnosis (NIPT) chromosome analysis, maternal blood samples are taken starting from the 10th week of pregnancy at 21, 13 and 18 weeks of pregnancy. It can be performed for th chromosome anomalies, both trisomy and structural disorders.On average, results can be achieved within 7 days. NIPT screening test diagnoses trisomy-21, trisomy-13, trisomy-18, trisomy-X, Turner syndrome, Klinefelter syndrome, Jacobs syndrome along with 1p36 deletion, 4p-,5p-, 5q11, 22q11 (Di-George syndrome). . This method is non-invasive for the mother as it is screened only by taking blood. Chromosomal studies are performed by separating the fetal DNA from the maternal blood, as well as new generation sequencing of the entire genome, so that the necessary diagnosis can be made. Recent studies have brought the reliability rate of this test very close to 100 percent. "In these applications, the relevant physician and medical geneticist must evaluate the patient, and the family and the expectant mother must be guided regarding which test should be performed, accompanied by genetic counseling," he said.

SOURCE: HEALTHACTUAL