As a result of recent changes to the national genomic test directory for rare diseases (opens in a new tab), East Genomics is simplifying test options for developmental disorders.
Removal of R53 Fragile X clinical indication
East Genomics can no longer accept referrals for R53 after the 15th March 2025.
Fragile X testing has a very low diagnostic yield (~ 0.35%), and therefore comprehensive testing is preferable for eligible patients. Expansions in the FMR1 gene can now be detected via whole genome sequencing (WGS) in place of the R53 Fragile X standalone test.
| Test | Application |
|---|---|
|
Test
R27 Paediatric disorders |
Application
Diagnostic testing for Fragile X syndrome via WGS |
|
Test
R240 Diagnostic/ R242 Predictive/R244 carrier testing for a familial variant |
Application
FMR1 targeted test for patients with a family history of Fragile X syndrome |
|
Test
R54 Hereditary ataxia with onset in adulthood* |
Application
Diagnostic testing for Fragile X associated tremor/ataxia syndrome (FXTAS) via WGS |
|
Test
R402.2 Premature ovarian insufficiency* |
Application
FMR1 targeted test for patients eligible under R402 clinical indication |
*Adult clinical indications unrelated to developmental disorders referrals where FMR1 expansion testing is warranted
Changes to clinical indications R27 (Paediatrics disorders) and R28 (Congenital malformation and dysmorphism syndromes-microarray)
R27 Paediatric disorders (WGS) testing now has expanded eligibility criteria and additional referring specialties, allowing more comprehensive use. Patients previously eligible for R29 Intellectual disability are now eligible for R27.
The eligibility criteria for R28 congenital malformation and dysmorphism syndromes (microarray only) now require suspicion of a specific chromosomal cause: “Clinical features should be highly suggestive of a chromosomal cause. Where possible, the specific chromosomal disorder that is suspected should be included on the request form.”
Which test should you be requesting?
We encourage all referrers for congenital malformation/dysmorphism and/or global delay/intellectual disability to first consider referring patients for a WGS test under R27 Paediatric disorders (see recommended pathway in figure below).
- The expanded referring specialisms and eligibility criteria for R27 make this test suitable for a wide range of patients with congenital malformations or moderate/severe global delay or intellectual disability. R29 (WGS)/R377 (microarray only) are still available to order.
- Referring for R27 WGS directly avoids multiple referrals and re-analysis when a diagnosis is not reached analysing R29 WGS/R377 (microarray only).
- WGS provides comprehensive testing more likely to yield a diagnosis than the standalone microarray test. WGS testing can detect most genomic abnormalities that would be expected to be found using microarray. Microarray testing alone should not be used as a screening test for genetic conditions.
- Referral as trio (child and both parents) is strongly encouraged. Trio analysis increases the chance of a diagnosis for the child and decreases results of uncertain significance and incidental findings. You can watch our Paediatrics Forum on this topic (opens in a new tab).
Please contact your local East GLH laboratory (opens in a new tab) for additional information.