Microarray Recommendations for Duchenne Muscular Dystrophy (DMD) and Spinal Muscular Atrophy (SMA)
Chromosomal Microarray Analysis (CMA) is a powerful genetic tool with applications across pediatrics, neonatology, and clinical genetics. One of the most frequent questions clinicians ask is:
👉 “Which type of microarray should be used to detect exon deletions and duplications, for example in Duchenne Muscular Dystrophy (DMD) or Spinal Muscular Atrophy (SMA)?”
Here’s a practical guide to help answer that.
Microarray and Exon Deletions/Duplications
All types of arrays (High Density – HD, Low Density – LD, Ultra-Low Density – ULD) can detect large deletions (dels) and duplications (dups).
HD arrays offer superior resolution and can identify smaller deletions/duplications that lower-resolution platforms might miss.
Since it is impossible to predict the size of the abnormality in advance, HD arrays are recommended whenever possible.
If cost is a limiting factor, LD or ULD arrays can still be used, but with the caveat that smaller changes may be missed.
Microarray Testing for DMD (Duchenne Muscular Dystrophy)
DMD is caused by mutations in the DMD gene, one of the largest genes in the human genome.
~60% of DMD patients have exon deletions or duplications, which can be detected by microarray testing.
The remaining ~40% of patients have point mutations or small sequence changes that cannot be picked up by microarray but can be identified by DNA sequencing.
Recommended Testing Strategy for DMD:
Start with Microarray Testing – to detect deletions/duplications.
If microarray is negative – proceed with gene sequencing to identify smaller mutations.
This combined approach ensures maximum detection rate for DMD patients.
Microarray Testing for SMA (Spinal Muscular Atrophy)
SMA is caused by mutations in the SMN1 gene, which is very small compared to DMD.
Since the mutations are tiny exonic changes, microarray is not recommended for SMA diagnosis.
Instead, a specific gene assay for SMN1/SMN2 is required, which provides much higher sensitivity.
LABASSURE Recommendations
For DMD: Begin with HD microarray → if negative, follow up with gene sequencing.
For SMA: Order a dedicated SMN1 gene test instead of microarray.
For clinicians: Always consider both clinical presentation and testing strategy to ensure accurate diagnosis.
At LABASSURE, we provide state-of-the-art microarray testing and specialized gene assays for conditions like DMD and SMA, along with expert genetic counseling for patients and families.
Key Takeaways
HD microarray is preferred for exon deletion/duplication detection.
DMD: 60% detectable by microarray, 40% require sequencing.
SMA: Microarray not suitable—specific SMN1 assay is required.
LABASSURE provides a stepwise, accurate, and cost-effective testing strategy for both conditions.
📧 For more information on DMD and SMA genetic testing in India, contact us at info@labassure.com
