Chromosomal misalignment, the loss or addition of one or more chromosomes (chromosomes), is the most common chromosomal disorder in humans. In particular, trisomy (Trisomy – a mutation with an extra chromosome in the same chromosome) accounts for the highest proportion and is one of the main causes of congenital malformations as well as mental retardation and motor.
Therefore, early detection and intervention when the fetus suffers from chromosome abnormalities is extremely important. The QF-PCR technique has been developed for this purpose.
What’s QF- PCR ?
Quantitative fluorescence – Polymerase Chain Reaction or quantitative fluorescent PCR, or QF-PCR for short, uses PCR techniques to specifically amplify STR segments – short, repeated DNA fragments Fluorescence marked and quantified by capillary electrophoresis.
The QF-PCR assay can identify abnormalities in some chromosomes: 13,18,21, X, Y.
Each chromosome will be surveyed at different STR. Because the selected STR loci often have high polymorphic properties, it is rare for the trisomy case to give inconclusive results. The QF-PCR assay investigates 26 different STR segments on chromosomes 13, 18, 21, X and Y
Currently the QF-PCR test is usually indicated in the rapid diagnosis of chromosomal disorders for high-risk pregnancies in Down Syndrome, Edwards Syndrome, Turner Syndrome, Klinefelter Syndrome …
QF-PCR – Objects of implementation:
Cases of high-risk pregnancy with chromosomal disorders that have been screened for a high risk of amniocentesis and prenatal diagnosis will be screened by a history of birth defects, tests and ultrasound. screening by maternal serum such as: Double test, Triple test, NIPT high risk of giving birth to birth defects
– Fetal ultrasound has abnormal images: the distance around the back of the neck is ≥ 3mm, a lack of bone in the nose, clenched fists, crooked feet, some abnormalities such as heart defects, gastrointestinal deformities …
– Pregnant women over 35 years old
– History of pregnancy or childbirth with inherited disease
– Pregnant women and / or husbands with chromosomal abnormalities or family history of genetic diseases.
Types of samples that can be used for this test include: amniotic fluid, placenta, umbilical cord, umbilical cord blood, miscarriage tissue …
QF-PCR – Diagnosis of common diseases related to chromosome abnormalities:
- Trisomy 21: Down syndrome
- Trisomy 18: Edwards syndrome
- Trisomy 13: Patau’s syndrome
- X and Y sex chromosomes:
- Turner syndrome: XO (single infection)
- Klinefelter syndrome: XXY
- Other chromosomal abnormalities: XXX; XYY
QF-PCR – Analysis results:
Trisomy 21 results (Down Syndrome)