You asked your doctor about your child's undiagnosed condition. They ordered a Whole Exome Sequencing (WES) test. Weeks later, a dense technical PDF arrived — pages of gene names, variant IDs, and classifications you've never seen before. You're not alone in feeling lost.
This guide explains exactly what each part of your WES report means, in plain language — so you can make confident decisions for your family.
What Is Whole Exome Sequencing (WES)?
Your DNA contains approximately 3 billion base pairs. Inside that code are around 20,000 genes — segments that carry the instructions for building proteins your body needs. The "exome" is the protein-coding part — roughly 1–2% of the full genome, but responsible for about 85% of known disease-causing mutations.
WES reads every letter of your exome and compares it against a reference genome to find variations. It is most commonly ordered for children with multiple unexplained medical problems, rare disease workups, and hereditary cancer risk assessment.
WES vs full genome: WES reads ~20,000 protein-coding genes. Whole Genome Sequencing (WGS) reads everything — including non-coding regions. For most clinical diagnoses, WES is sufficient and more cost-effective.
The 5 Variant Classification Categories
Every variant found in your WES report is classified into one of five categories using international ACMG guidelines. This is the most important part of your report.
Strong scientific evidence confirms this variant causes the condition being investigated. This is a definitive diagnosis. Clinical action is required — your doctor and genetic counselor will discuss management, surveillance, and family implications.
Evidence strongly suggests this variant is disease-causing. In clinical practice, Likely Pathogenic variants are managed the same as Pathogenic ones. Most labs reclassify these as Pathogenic within a few years as evidence accumulates.
The most common and most confusing result. A VUS is not a diagnosis — it simply means current evidence is insufficient to classify it. VUS results should not drive major clinical decisions on their own. Many are eventually reclassified — most downward to Benign, some upward to Pathogenic.
Evidence suggests this is a normal, benign variation. These are typically not reported or listed for informational purposes only. No clinical action required.
Strong evidence confirms this is a normal population variant with no disease association. It may not appear in your report at all.
Important: A WES report with "no pathogenic variant found" does not mean you don't have a genetic condition. WES cannot detect all variant types — large deletions, copy number variants, and intronic variants may need additional tests.
Understanding VUS — Variant of Uncertain Significance
- A VUS is not a diagnosis and not a reassurance
- VUS results should not drive major medical decisions on their own
- Labs continuously reclassify VUS results — request updates at 12–18 months
- Context matters enormously — a genetic counselor interprets VUS against your clinical presentation
If your report contains a VUS: A genetic counselor can help you understand its significance in context of your specific symptoms and family history — which a lab report alone cannot provide.
WES vs WGS — What's the Difference?
| Feature | WES | WGS |
|---|---|---|
| What is sequenced | Protein-coding genes (~1–2%) | Entire genome (100%) |
| Diagnostic yield (rare disease) | 25–40% | 35–50% |
| Cost in India (approx.) | ₹15,000–₹40,000 | ₹40,000–₹1,00,000+ |
| Turnaround time | 4–8 weeks | 6–12 weeks |
| Best for | Most rare disease workups | When WES is negative but suspicion remains high |
What to Do After Receiving Your WES Report
- Do not interpret it alone. WES reports are written for geneticists, not for patients or GPs.
- Book a genetic counseling session. A certified counselor will review the report against your clinical presentation and family history.
- Ask about parental/trio testing. Testing parents can help reclassify a VUS result dramatically.
- Ask about functional studies — RNA studies or enzyme assays can provide evidence to reclassify VUS variants.
- Request VUS reclassification updates from the lab at 12–18 months post-report.
Getting WES Interpreted in India
WES is available across India from labs including MedGenome, Neuberg Supratech, Genotypic Technology, and international labs (GeneDx, Blueprint Genetics). However, ordering the test is very different from interpreting it correctly for an Indian patient.
India-specific challenge: Most genomic databases are built on European cohorts. Variants common in the Indian population may be misclassified as VUS because they're rare in these databases. An Indian genetic counselor understands which variants are likely population-specific.
Frequently Asked Questions
Not necessarily. A negative WES result means no disease-causing variant was found in the regions tested. Some conditions are caused by variants in non-coding regions (not covered by WES), or by copy number variants that standard WES may miss. If clinical suspicion remains high, further testing (WGS, chromosomal microarray) may be recommended.
Typically 4–12 weeks, depending on the lab and test type. Trio WES (patient + parents) takes longer. Indian labs (MedGenome, Neuberg) are generally faster. International labs (GeneDx, Blueprint) may take 6–12 weeks.
It depends on the inheritance pattern. Autosomal dominant: 50% chance each sibling is affected. Autosomal recessive: both parents are typically carriers, 25% risk per sibling. De novo (new mutation): risk to siblings is low but not zero. A genetic counselor will review the specific variant and explain the family implications.
Yes, absolutely. WES reports are standardised documents you are entitled to share. A second opinion is particularly valuable when your report contains a VUS, or when you received the report without any counseling. MyGeneScreen Clinic provides second-opinion interpretation sessions for ₹1,500.
Most Indian health insurance plans do not cover WES. Some corporate policies and government schemes (CGHS for rare diseases) may offer partial coverage. The genetic counseling interpretation session (₹1,500) is separate from the lab cost.
Got Your WES Report and Don't Know Where to Start?
Book an interpretation session with Lakshita Thakore, BGCI Certified Genetic Counselor — in-person in Ahmedabad or online anywhere in India. We review your report, explain every finding in plain language, and tell you exactly what to do next.
Book WES Interpretation Session — ₹1,500