Chromosomal Microarray in Detection of Prenatal Submicroscopic Chromosome Abnormalities

Chromosomal Microarray in Detection of Prenatal Submicroscopic Chromosome Abnormalities

Authors: Sukrut Jobanputra, Chanchal Singh Ahmad, Ratna Puri, Anushka Shrivastava, Brijesh Kumar, Tara Nath, Vaidehi Jobanputra
Institution: Advanced Genomics Institute & Laboratory Medicine (AGILE)
Collaboration Partners: Apollo Centre for Fetal Medicine, Sir Ganga Ram Hospital
📧 Email: info@labassure.com

Introduction

Chromosomal Microarray Analysis (CMA) is an advanced genetic test that scans the entire genome to detect:

• Copy Number Variants (CNVs): Microdeletions and microduplications (gain/loss of DNA).

• Copy-neutral abnormalities: Loss of heterozygosity (LOH), uniparental disomy (UPD), and long stretches of homozygosity.

This single test provides information on thousands of genes at once and has become a powerful diagnostic tool in prenatal genetics, particularly in:

• Fetuses with ultrasound-detected anomalies

• Stillbirth cases

• Pregnancies with abnormal maternal serum screening

Objective

To demonstrate the utility of microarrays in detecting prenatal submicroscopic chromosomal abnormalities, particularly when traditional karyotyping appears normal.

Methodology

Chromosomal microarray testing was performed on prenatal samples (Amniotic Fluid) using advanced arrays:

• CytoScan® HD Array

• CytoScan® 750K Array

The arrays enabled:

• Detection of LOH (Loss of Heterozygosity)

• Identification of Uniparental Disomy (UPD)

Data was analyzed using Chromosome Analysis Suite (ChAS) Software, and clinical interpretation was provided by ABMG-certified geneticists, ensuring accurate genotype–phenotype correlation.

Results

A total of 34 prenatal samples were analyzed from partner institutions. Clinical indications included:

• Fetus with ultrasound abnormality: 21 cases

• Abnormal maternal serum screening: 3 cases

• Previous child with chromosomal abnormality: 10 cases

Out of these 34 cases with normal karyotypes, 7 were found to carry clinically significant abnormalities detectable only by CMA.

Conclusion

This study highlights that Chromosomal Microarray Analysis (CMA) provides far greater diagnostic accuracy compared to conventional cytogenetic methods such as karyotyping.

Key Findings:

• CMA identified submicroscopic abnormalities missed by karyotyping.

• Provided clearer causality for fetal growth restriction (IUGR) and structural abnormalities.

• Enabled recurrence risk assessment, crucial for genetic counseling.

• In some cases, even when termination was already decided based on ultrasound findings, CMA offered valuable genetic insights for future reproductive planning.

• CMA is also useful in Products of Conception (POC) analysis, providing answers in cases of miscarriage or stillbirth.

👉 Practical Value: CMA delivers accurate, clinically actionable genetic information, empowering patients and physicians to make informed decisions regarding diagnosis, prognosis, and pregnancy management.

LABASSURE Advantage

At LABASSURE, we offer high-resolution chromosomal microarray testing with:

• Validated global platforms (CytoScan HD & 750K)

• Expert clinical interpretation by certified geneticists

• Comprehensive genetic counseling support for families and clinicians

This ensures that every CMA report is not just a lab output but a clinically meaningful diagnosis.

📧 To learn more about Prenatal Chromosomal Microarray Testing in India, write to us at info@labassure.com