CMA (Chromosomal Microarray) — What, Who, Why, When, and Where
By Anu Acharya, MapmyGenome
CMA (Chromosomal Microarray) is a powerful genetic diagnostic test usually advised by paediatricians or obstetricians for children with developmental issues, birth defects, or Autism Spectrum Disorder (ASD), or for couples during or after pregnancy. Here is a plain-language guide to everything you need to know.
What Is CMA?
CMA looks for extra (duplicated) or missing (deleted) chromosomal segments — called copy number variants (CNVs). Unlike a standard karyotype (which counts chromosomes), CMA uses 700,000 markers to detect submicroscopic deletions and duplications that are invisible to karyotyping but can still have a significant impact on development. CMA can also detect:
Microdeletions and microduplications of chromosome segments
Aneuploidy (extra or missing whole chromosomes, e.g. Down syndrome)
Excessive homozygosity, suggestive of recessive disease or imprinting disorders
Mosaicism (a mix of normal and abnormal cells)
Who Should Get CMA?
Children with impaired physical development, delayed milestones, or intellectual disability
Children with Autism Spectrum Disorder, ADD, or ADHD
Children with multiple congenital anomalies or dysmorphic features
Couples with recurrent pregnancy loss or unexplained infertility
Prenatal diagnosis when ultrasound findings are abnormal
Why CMA?
CMA has a diagnostic yield of 15–20% in children with developmental delay — compared to 3–5% for standard karyotyping. It comprehensively examines all chromosomes for gains and losses in a single test, helps families plan future pregnancies, and can influence medical management through targeted lifestyle and therapeutic interventions.
When Is CMA Done?
Prenatal — 8–13 weeks of pregnancy, to inform decisions about pregnancy management
Postnatal — after delivery, on signs of developmental delays, ASD, seizures, or birth defects
POC (Product of Conception) — in cases of miscarriage, stillbirth, or medical termination, to understand recurrence risk
Where Can You Get CMA?
CMA is available at MapmyGenome. The test can be ordered online at www.mapmygenome.in or at your doctor’s clinic or hospital. Genetic counselling is strongly recommended alongside CMA to help interpret results and plan next steps.
Expert Genetic Counselling for CMA and Chromosomal Testing
MapmyGenome’s certified genetic counsellors provide expert guidance for families navigating chromosomal microarray results, developmental delay, ASD, and congenital anomaly diagnoses. Available online across India.
