Genomic diagnostics · London
Whole exome sequencing (WES), read by a clinical geneticist, not a portal.
WES sequences the roughly 19,000 protein-coding genes that account for 85 per cent or more of known disease-causing mutations. It is the diagnostic test of choice when a rare genetic condition is suspected but the phenotype cannot be narrowed to a single-gene panel.
Clinical indications
When exome sequencing is the right next step.
WES is used when clinical suspicion cannot be narrowed to one gene or panel. Diagnostic yield is 25 to 40 per cent for proband testing and 40 to 50 per cent for family trios.
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Undiagnosed rare genetic disease
Child or adult with a phenotype that cannot be narrowed to a single-gene panel after specialist workup.
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Intellectual disability and autism
Unexplained developmental delay, cognitive impairment, or autism where clinical clues do not point to one gene.
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Unexplained epilepsy syndromes
Seizure disorders that have not responded to first-line treatment or have atypical features.
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Suspected metabolic disorder
Biochemical findings suggestive of an inborn error of metabolism without a clear molecular diagnosis.
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Suspected mitochondrial disease
Multisystem involvement, lactic acidosis or muscle biopsy findings that suggest mitochondrial dysfunction.
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Unexplained cardiomyopathy or arrhythmia
Familial or early-onset cardiac disease where panel testing has been negative or non-diagnostic.
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Bone marrow failure or immunodeficiency
Unexplained cytopenias, primary immunodeficiency or recurrent unusual infections.
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Multiple congenital anomalies
Infants with several structural anomalies where a unifying syndromic diagnosis is suspected.
Indicative pricing
Honest ranges, private and NHS.
Ranges reflect the London private market and the NHS Genomic Medicine Service. We quote firm figures within one working day.
| Test type | Indicative range | Sample | Turnaround |
|---|---|---|---|
| Proband-only WES | £1,600 to £3,500 | Blood sample | 6 to 12 weeks |
| Trio WES (child plus both parents) | £2,800 to £5,500 | Blood samples x3 | 6 to 12 weeks |
| Rapid WES (critically unwell) | £4,500 to £8,000 | Blood sample | 2 to 4 weeks |
| Reanalysis after 2 to 3 years | £350 to £750 | No new sample | 4 to 8 weeks |
| NHS Genomic Medicine Service | Free (eligibility criteria apply) | Blood sample | 6 to 12 months |
The pathway
From consent to consultation.
Every step is led by a consultant clinical geneticist or paediatric neurologist. Nothing is dispatched without a proper consent conversation.
- 01
Clinical genetics review
A consultant clinical geneticist or paediatric neurologist takes a detailed phenotype using HPO terms and a three-generation pedigree.
- 02
Informed consent
A structured consent conversation covering secondary findings, insurance implications, cascade testing and psychological support.
- 03
Sample collection
A single blood draw for the proband. For a trio, both biological parents are sampled the same day where possible.
- 04
Sequencing and analysis
The exome is sequenced and variants are filtered against the phenotype. Trio analysis distinguishes inherited from de novo variants.
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ACMG classification
Variants are reported as pathogenic, likely pathogenic, or variants of uncertain significance (VUS) using ACMG criteria.
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Results consultation
A follow-up appointment explains findings, cascade testing for relatives, and reproductive or management implications.
How WES compares
Not every question needs an exome.
Where the clinical question is narrower, a panel or single-gene test is often faster and cheaper.
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Single-gene testing
Cheaper and faster where a specific familial mutation is known. Not suitable for undiagnosed presentations.
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Targeted gene panels
Cheaper and faster than WES for narrow indications such as hereditary cancer or cardiomyopathy panels.
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Whole genome sequencing (WGS)
Sequences non-coding regions too. More comprehensive but £8,500 and above privately, with longer turnaround.
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Hereditary cancer panels
Focused on 20 to 90 cancer-predisposition genes. Preferred first-line for cancer family history.
Related reading: whole genome sequencing, pharmacogenomic testing, hereditary cancer panel, polygenic risk score, BRCA testing, paediatric allergy testing, epigenetic age testing, rare disease.
What to consider
A test with real weight, done properly.
WES is safe as a blood test, but the results have implications for you, your relatives and future decisions. Consent is not a tickbox.
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Secondary findings (ACMG SF list)
Around 78 medically actionable genes may be reported incidentally if you consent. These include cardiac, cancer and metabolic conditions.
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Variants of uncertain significance
VUS results require further evaluation. They should not be used for clinical decisions until reclassified.
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Insurance implications
Under the ABI Concordat 2018, UK insurers cannot request predictive genetic test results except for Huntington disease on life cover above £500,000.
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Family implications
Germline results affect blood relatives. Cascade testing is offered to first-degree relatives where a pathogenic variant is identified.
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Reproductive decisions
A confirmed diagnosis may open pre-implantation genetic testing or prenatal diagnosis in future pregnancies.
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Psychological support
Genetic counselling is included before and after testing. A confirmed or uncertain result can be emotionally significant.
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Reanalysis
Repeating variant analysis every 2 to 3 years increases diagnostic yield as new disease genes are discovered.
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Diagnostic yield
Proband WES yields a diagnosis in 25 to 40 per cent of rare disease cases. Trio WES improves this to 40 to 50 per cent.
Frequently asked
What we get asked before people book.
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What is the difference between WES and whole genome sequencing?
WES sequences the roughly 1 to 2 per cent of the genome that codes for proteins, covering about 19,000 genes and 85 per cent or more of known disease-causing mutations. WGS also sequences non-coding regions and is more comprehensive, but costs from £8,500 privately and takes longer to analyse. For most rare disease presentations, WES is the pragmatic first choice.
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Why is trio testing recommended?
Sequencing the child alongside both biological parents lets the laboratory distinguish inherited variants from new (de novo) mutations. This raises the diagnostic yield from 25 to 40 per cent for a proband-only test to 40 to 50 per cent for a trio, and reduces the number of variants classified as uncertain.
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Can I get WES on the NHS?
Yes, through the NHS Genomic Medicine Service via a clinical genetics or specialist referral, provided the clinical indication meets the National Genomic Test Directory criteria. Private testing is used when the NHS turnaround (typically 6 to 12 months) is too slow, when the indication falls outside NHS eligibility, or when family circumstances make private testing preferable.
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Will my results affect my life insurance?
Under the ABI and UK Government Concordat and Moratorium on Genetics and Insurance (2018), UK insurers cannot ask for or use the results of predictive genetic tests, with a single exception: predictive Huntington disease results for life insurance policies above £500,000. Diagnostic testing to explain existing symptoms is treated differently from predictive testing and should be discussed with your geneticist before testing.
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What are secondary findings and do I have to receive them?
The American College of Medical Genetics maintains a list of around 78 genes where a pathogenic variant is medically actionable, such as familial cancer syndromes or inherited heart conditions. If you consent, the laboratory will report these even if they are unrelated to your original reason for testing. You can opt out during the consent conversation.
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What happens if my result comes back as a VUS?
A variant of uncertain significance is a change in a gene where the evidence is not yet strong enough to call it pathogenic or benign. VUS results should not drive clinical decisions on their own. We recommend reanalysis every 2 to 3 years, as gene discovery and variant databases continue to expand and many VUS results are eventually reclassified.
Speak to a clinical geneticist
The right test, the right consent, the right conversation about what a result means.
Tell us the clinical question. We come back within one working day with the appropriate test, indicative cost, and a consultant clinical genetics appointment where needed.