Chromosomal Microarray (CMA) - Prenatal

Chromosomal Microarray (CMA) is a cutting-edge diagnostic tool designed to detect submicroscopic chromosomal deletions and duplications, known as copy number variants (CNVs). These CNVs are responsible for various genetic disorders, including intellectual disabilities, autism spectrum disorders, and congenital anomalies. Unlike traditional karyotyping, which is limited in resolution, CMA offers a high-resolution, whole-genome approach to identify even the smallest chromosomal imbalances. The American College of Medical Genetics (ACMG) endorses microarray technologies like CMA as a first-tier test for evaluating intellectual disability, autism, and multiple congenital anomalies. This prenatal testing method is essential for providing accurate genetic insights and guiding clinical decision-making.

CMA involves analyzing a patient’s genome using microarray technology to detect CNVs that may not be visible under a microscope. CNVs occur when sections of the genome are duplicated or deleted, leading to potential genetic disorders. While traditional karyotyping focuses on larger chromosomal changes, CMA delves deeper into the genetic landscape, identifying even the most subtle variations that can affect fetal development.

Clinical Utility

CMA offers numerous clinical advantages, making it an invaluable tool for prenatal diagnosis. Some of the key applications include:

1. Detection of Chromosomal Imbalances: CMA identifies submicroscopic CNVs, which are associated with intellectual disabilities, autism, and congenital abnormalities. It helps to diagnose conditions that are missed by traditional karyotyping, improving clinical outcomes.

2. Differentiation Between De Novo and Familial Disorders: CMA can distinguish whether a CNV is a new mutation or inherited from a parent, which is crucial for understanding recurrence risks in future pregnancies.

3. Prenatal Diagnosis of At-Risk Pregnancies: CMA is particularly useful in cases of high-risk pregnancies where structural abnormalities have been identified through ultrasound. It provides a more comprehensive view of fetal chromosomal health, guiding appropriate management.

4. Guiding Management of Genetic Conditions: CMA results offer critical insights into the severity and type of genetic disorder present. This information influences treatment and management strategies, including lifestyle modifications and medical interventions.

5. Screening for Uniparental Disomy (UPD): In rare cases, UPD occurs when both copies of a chromosome come from one parent. CMA detects such anomalies, enabling better diagnosis and management of the associated disorders.

6. Family Planning and Genetic Counseling: CMA helps healthcare providers offer detailed genetic counseling to families, informing them about the potential risks and guiding future reproductive decisions.
   
   

When to Consider CMA Prenatal Testing

CMA is recommended in several prenatal scenarios, particularly when there is a higher risk of chromosomal abnormalities:

1. Abnormal Ultrasound Findings: If one or more structural abnormalities are detected via ultrasound, CMA can provide a clearer picture of any underlying chromosomal anomalies.

2. Abnormal Maternal Serum Screening: An abnormal result from a maternal serum screening test can indicate the need for CMA to detect the presence of chromosomal imbalances that could be causing the abnormality.

3. Advanced Maternal Age: Women aged 35 or older are at a higher risk of giving birth to children with chromosomal abnormalities. CMA provides a comprehensive genetic screening option in such cases.

4. Family History of Genetic Disorders: If there is a family history of genetic diseases or chromosomal abnormalities, CMA can help assess the risk of passing these conditions to the child.

5. Consanguinity: In families where parents are related by blood, there is an increased risk of recessive genetic disorders. CMA helps in identifying these risks early.

6. Pregnancy Loss or Stillbirth: Recurrent pregnancy loss or stillbirth may be caused by undetected chromosomal abnormalities. CMA aids in diagnosing the genetic cause behind such outcomes, providing insights into future pregnancies.

7. Unexplained Intellectual Disabilities or Autism in Family History: CMA is recommended for parents with a family history of unexplained intellectual disabilities, autism, or congenital anomalies, as it can help identify potential genetic causes.
   
   

MapmyGenome CMA Offerings

At MapmyGenome, we offer advanced prenatal CMA testing using Illumina 750K BeadChip technology, optimized for high-resolution cytogenetic analysis. Our CMA services include:

1. Comprehensive Genome Analysis: Our CMA testing covers 750,000 markers across ~9,000 genes, with a focus on 447 disease-associated genes. This allows for detailed and accurate genetic analysis.

2. Copy Number Variation Detection: We detect CNVs as small as 2.3 kb, allowing us to identify even the smallest chromosomal changes that could have a significant impact on fetal development.

3. Detection of Uniparental Disomy (UPD): Our testing identifies UPD and other forms of copy-neutral loss of heterozygosity (Cn-LOH), which are critical for diagnosing rare genetic disorders.

4. Targeted Screening of Known Genetic Hotspots: We analyze 324 known cytogenetic regions, commonly associated with genetic disorders, ensuring that your test results are both comprehensive and clinically relevant.

5. Extensive Database Integration: Our results are cross-referenced with over 495,000 genomic structural variants from the Database of Genomic Variants, enhancing the interpretation and clinical significance of detected anomalies.

Test specification

 

Learn more:

Read: Dive Into CMA: Uncovering Prenatal Chromosomal Insights

Listen: Decoding Prenatal Genetics with CMA

Watch: Understanding CMA for Prenatal Genetic Screening