Sex determination using free fetal DNA in early pregnancy: With the approach to sex linked recessive disorders

Amir Monfaredan,Shahrokh Amiri,Seyed Mahmoud Tabatabaei

doi:10.15171/jarcm.2017.004

Abstract

Introduction: Prenatal diagnosis is testing for detection of diseases or conditions in a fetus or embryo before it is born. Most of prenatal diagnostic (PD) techniques are invasive and done in late stages of pregnancy. Using fetal DNA in maternal blood for fetal sex determination in early pregnancy might help in management of X-linked genetic diseases. This study aimed to investigate the accuracy of sex determination using fetal DNA in maternal blood at 8-12 weeks of gestation. Methods: In this cross-sectional study, 30 pregnant women at 8-12 weeks of gestation were enrolled. The sex-determining region Y (SRY) gene expression with the internal control (IC) glyceraldehyde 3-phosphate dehydrogenase (GAPDH) was investigated with quantitative real-time polymerase chain reaction (PCR) using specific primers and probes. Results: Accuracy of sex determination with SRY gene expression in 8-12 weeks of pregnancy were 85%, 85%, 90% and 100% respectively. Conclusion: It seems that fetal sex determining using fetal DNA in maternal blood is a reliable method for early stage of pregnancy.

Highlights

Prenatal diagnosis is testing for detection of diseases or conditions in a fetus or embryo before it is born
In women who are carriers of X-linked conditions, the early fetal sex determination using cell-free fetal DNA can be performed by non-invasive testing. In this experimental study, the aim was to investigate the presence of sex-determining region Y (SRY) gene, the specific gene on Y chromosome
Using a vacuum blood sample system, 5 ml of peripheral blood was obtained from 30 pregnant women at 8 to 12 gestational week, with intervals of 5 hours into ethylenediaminetetraacetic acid (EDTA) tubes

Summary

Introduction

Prenatal diagnosis is testing for detection of diseases or conditions in a fetus or embryo before it is born. Using fetal DNA in maternal blood for fetal sex determination in early pregnancy might help in management of X-linked genetic diseases. Indications for PD include high risk situations for chromosomal abnormalities in the fetus, such as high maternal age, balanced translocation in one parent, history of previous child with a chromosomal abnormality, structural defects in one of the parents chromosomes (mosaicism, pericentric, inversion), fragile X syndrome, or family with a single gene disorders child (recessive, dominant or sex-linked, like metabolic inherited disorders, maple syrup urine disease, phenylketonuria, galactosemia, etc.) or diseases with ethnic background (Tay-Sachs, cystic fibrosis, thalassemia), history of recurrent spontaneous abortion, Sex determination using free fetal DNA in early pregnancy risk of neural tube defects (NTD) as well as multiple anomalies in previous newborn.[2,3,4]

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