Diagnosis-led treatment
Getting a precise diagnosis
Exome and genome sequencing, panels, metabolic work-up, MRI
For a family weighing expensive treatments abroad, this is almost always the better place to spend the money first. A name can unlock a licensed medicine — or rule one out.
Either a medicines regulator has licensed it for this use, or clinical practice guidelines recommend it on the strength of controlled trials. This is the standard everything else on the scale is measured against — and for most children, the treatments at this level are the ones that will actually change their day.
Where it stands, condition by condition
The same therapy can be well supported for one problem and completely untested for another. This is the single most common place families are misled.
| Condition | Evidence | What that means here |
|---|---|---|
| Developmental delay, intellectual disability, epilepsy of unknown cause | Established care | Exome or genome sequencing is recommended as a first-tier test in international guidance, with diagnostic yield that no amount of further imaging matches. |
| Cerebral palsy without a clear injury on MRI | Established care | A meaningful proportion of children labelled cerebral palsy have an underlying genetic condition. Where the history and MRI do not explain the picture, genetic testing is indicated. |
| Early-onset epileptic encephalopathy | Established care | Diagnosis frequently changes treatment directly — some genes make particular antiseizure medicines the right choice and others actively harmful. |
| Neuromuscular presentations | Established care | Newborn screening and early genetic diagnosis in spinal muscular atrophy exist precisely because treatment before symptoms changes the outcome. |
What it is
Sequencing the child's genes — as a targeted panel, as an exome, or as a whole genome — alongside imaging and, where indicated, metabolic testing.
Testing the parents at the same time (a “trio”) makes interpretation substantially easier, because a variant present in a healthy parent is usually not the answer.
This is not an academic exercise. It is the step that decides whether any disease-modifying treatment is available to your child at all.
How it is meant to work
Rehabilitation treats the consequences. A genetic diagnosis occasionally lets you treat the cause — and increasingly often, it tells you which ordinary medicine to choose or avoid.
It also ends the diagnostic odyssey, gives a prognosis that is at least grounded, identifies what to monitor for, informs decisions about future children, and opens access to a condition-specific family community and to trials.
A negative result is not a wasted test. It rules out the treatable conditions, and stored data can be reanalysed as new genes are described — which happens continually.
What has actually been tested
- Exome and genome sequencing have the highest diagnostic yield of any single investigation in unexplained developmental and neurological presentations, and professional guidance now places them early rather than last.
- The clinical consequences are concrete. In spinal muscular atrophy, diagnosis before symptoms begin, through newborn screening, changes what treatment can achieve — which is why many countries screen.
- In genetic epilepsies, the diagnosis routinely changes prescribing: some sodium-channel conditions respond to medicines that are harmful in others. Treating the syndrome blind risks making seizures worse.
- A GLUT1 transporter defect is the clearest example of a diagnosis that changes the whole plan — the treatment is dietary, and it will not be found without the test.
What we still do not know
- How to interpret variants of uncertain significance — a common and frustrating result that is neither answer nor exclusion.
- What proportion of currently undiagnosed children will be solved as knowledge grows; reanalysis every few years is reasonable.
- Access and funding, which vary enormously between countries and are the real limiting factor.
Risks and costs
- Uncertain results cause anxiety and can be over-interpreted by families and clinicians alike.
- Incidental findings unrelated to the question, which need discussion before testing rather than after.
- Implications for parents and siblings, which deserve proper genetic counselling rather than a results letter.
- The cost is real — but it is a fraction of one course of unproven cell therapy, and far more likely to change what happens next.
Questions to ask before you agree
A centre that is doing good work will welcome these questions and answer them in writing.
- Has my child had exome or genome sequencing, and if not, why not?
- Was it a trio with both parents?
- If the result was negative or uncertain, when will the data be reanalysed?
- Does the result change which medicines my child should or should not take?