Quick Genetic Testing for Chromosome Disorders

QF-PCR for Rapid Aneuploidy Detection

Quantitative Fluorescent Polymerase Chain Reaction (QF-PCR) is a molecular diagnostic technique for the rapid detection of common chromosomal aneuploidies involving chromosomes 13, 18, 21, X, and Y.

It analyzes highly polymorphic Short Tandem Repeat (STR) markers specific to these chromosomes. By quantifying the fluorescent signal from amplified STR alleles, QF-PCR can accurately determine the copy number of the target chromosomes.

Indications

Indications for QF-PCR Testing

QF-PCR is indicated for:

Prenatal Diagnosis (from Amniotic Fluid or CVS)

High-risk results from prenatal screening tests (NIPT, maternal serum screening).
Fetal ultrasound anomalies suggestive of trisomy 13, 18, or 21.
Previous pregnancy affected by a common aneuploidy.
Patient/parental anxiety requiring rapid reassurance or diagnosis.

Postnatal Diagnosis (from Blood)

Neonates with dysmorphic features or clinical suspicion of Down syndrome, Edwards syndrome, Patau syndrome, Turner syndrome, or Klinefelter syndrome.

Fetal Chromosome Analysis

Conditions Detected by QF-PCR

Condition	Chromosome(s) Involved	Clinical Impact	Typical Sensitivity
Down Syndrome	Trisomy 21	Intellectual disability, congenital anomalies	>99%
Edwards Syndrome	Trisomy 18	Severe growth retardation, multiple anomalies, poor survival	>99%
Patau Syndrome	Trisomy 13	Severe CNS defects, multiple anomalies, poor survival	>99%
Turner Syndrome	Monosomy X (45, X)	Short stature, ovarian dysgenesis, cardiac issues	>99%
Klinefelter Syndrome	47, XXY	Hypogonadism, learning disabilities, infertility	>99%
Other Sex Aneuploidies	47, XXX; 47, XYY	Variable phenotypes, often milder	>99%

Platform & Methodology

Methodology: How QF-PCR Works

DNA Extraction: DNA is isolated from the clinical sample (amniocytes, chorionic villi, blood cells).

Multiplex PCR: Specific polymorphic STR markers located on chromosomes 13, 18, 21, X, and Y are co-amplified using fluorescently labeled primers. Amelogenin (AMELX/AMELY) or other X/Y specific markers are used for sex determination and sex chromosome aneuploidy detection.

Capillary Electrophoresis: The fluorescent PCR products are separated by size using capillary electrophoresis.

Data Analysis: The fluorescent signal intensity and peak ratios for each STR marker are analyzed.

Normal: Two alleles with a 1:1 ratio (heterozygous) or one allele (homozygous).
Trisomy: Three alleles with a 1:1:1 ratio (triallelic), or two alleles with a 2:1 or 1:2 ratio (diallelic trisomy).
Monosomy X: Single X-specific allele detected, absence of Y-specific alleles.

Advantages

Advantages of QF-PCR

Rapidity

Primary advantage, allowing for timely clinical decisions.

Accuracy

High sensitivity and specificity for the targeted aneuploidies.

Automation

Amenable to high-throughput processing.

Cost-Effective

For rapid screening of common aneuploidies compared to broader genomic tests.

No Cell Culture

Reduces TAT and risk of culture failure.

Limitations

Limitations of QF-PCR

Limited Scope: Only detects aneuploidies for chromosomes 13, 18, 21, X, and Y.
No Detection of Structural Abnormalities: Balanced translocations, inversions, or microdeletions/microduplications outside the targeted chromosomes are not detected.
Mosaicism: May not detect low-level mosaicism or mosaicism confined to specific tissues not sampled.
Triploidy: Can detect triploidy but may require careful interpretation of marker patterns.
Uninformative Markers: Rarely, parental homozygosity for all tested markers on a chromosome can lead to an uninformative result for that chromosome.

Clinical Guidelines

Clinical Guidelines Supporting QF-PCR Use

NICE (UK), RCOG (UK) and other European guidelines: Recommend QF-PCR as a primary standalone test for rapid aneuploidy detection in suitable prenatal cases.
Often used as a first-line rapid test, with follow-up karyotyping or CMA considered depending on the clinical scenario and QF-PCR result.
ACMG/ACOG acknowledge rapid aneuploidy tests like QF-PCR or FISH for urgent results, often advising full karyotype or CMA for comprehensive analysis.

Sample Requirements & Processing

Sample Type	Collection Requirements	TAT
Amniotic Fluid (AF)	5-10 ml (minimum 2ml) in sterile, plain universal container	24-48 hours
Chorionic Villus (CVS)	5-10 mg villi in sterile transport medium or saline	24-48 hours
Peripheral Blood	1-3 ml in EDTA (purple top) tube	24-48 hours

Shipping Conditions: Room temperature. Avoid freezing or excessive heat. Ensure prompt delivery for optimal sample quality.

Why Choose Suraksha Genomics for QF-PCR Testing?

Rapid and Reliable Results: Advanced QF-PCR technology ensuring delivery within 24-48 hours.
High Sensitivity & Specificity: For detection of common trisomies and sex chromosome aneuploidies.
Experienced Team: Performed and interpreted by skilled molecular geneticists.
Integrated Services: Part of a comprehensive suite of prenatal and postnatal genetic tests, including genetic counseling.

Consult our experts

QF-PCR for Aneuploidy