Core Genomic testing

The National Genomics Test Directory for Rare Disease includes more than 500 genetic tests organised in Core and Specialists Service groups/referral pathways, to facilitate the identification of the most appropriate test for each clinical indication.

The rare and inherited diseases eligibility criteria document supplements the National Genomic Test Directory by setting out which patients should be considered for testing under that indication, and the requesting specialties is a list of the clinical specialties who would be expected to request the test.

The most common core clinical indications provided in WMRGL are listed below. Please see here for a letter detailing important information regarding recent changes to the National Genomic Test Directory relating to genomic testing of patients with intellectual disability and developmental delay which the Central and South Genomic Laboratory Hub will implement from 1st November 2024.

Genomic Testing Triage Form (for microarray test requests)

If you have referred your patient for microarray testing and the laboratory has requested additional information, please complete the Genomic Testing Triage Form. This form is for documenting the degree of intellectual disability, degree of global developmental delay and other phenotypes to ensure appropriate genomic testing selection and eligibility.

Developmental Disorders

• R26 Likely common aneuploidy
• R27 Congenital malformation and dysmorphism syndromes (microarray and WGS) — Microarray options, WGS recommended test
• R28 Congenital malformation and dysmorphism syndromes (microarray only) — Use where the patient has features strongly suggestive of a specific chromosomal disorder
• R29 Intellectual disability (WGS)
• R377 Intellectual disability (microarray only)
• R47 Angelman syndrome
• R48 Prader-Willi Syndrome
• R53 Fragile X 
• R69 Hypotonic Infant (microarray and WGS)
• R312 Parental sequencing for lethal autosomal recessive disorders

Other Core genomic testing

• R402 Premature ovarian insufficiency
• R314 Ambiguous genitalia presenting neonatally
• R411 Y chromosome microdeletion
• R24 Achondroplasia
• R65 Aminoglycoside exposure posing risk to hearing
• R70 Spinal muscular atrophy (SMA)
• R252 SMA carrier testing at population risk for partners of known carriers
• R184 Cystic fibrosis
• R185 Cystic fibrosis carrier testing
• R89 Ultra rare and atypical monogenic disorders
• R111 X-inactivation testing
• R244 Carrier testing for known familial variant(s)
• R246 Carrier testing at population risk for partners of known carriers of nationally agreed autosomal recessive disorders – Typically 1/70 carrier frequency cutoff for testing, contact laboratory if required
• Inherited cancer core tests
• Prenatal core tests

Please see the Letter to Service Users informing you of a change to our diagnostic practices, which has taken effect from November 4th 2024 and is of relevance to samples being referred for Chromosome Analysis.

Referrals and testing

Whole Genome Sequencing (WGS) tests

To request WGS please complete a copy of the Record of Discussion Regarding Genomic Testing and the Whole Genome Sequencing Test Request form . Testing for WGS cannot be initiated unless both forms have been fully completed.

Find out more about WGS and sample requirements.

All other tests

Referral form for non-WHS tests

Diagnostic referrals are accepted from the Consultant Specialists, as indicated in the National Genomics Test Directory 

Referrals for predictive testing are accepted only via Clinical Genetics.

It is essential that the referring clinician provides sufficient clinical information to assist in the interpretation of any findings (ie a copy of a recent clinical letter).

Sample requirements: 2-4 mls blood in EDTA or DNA samples. 2-4 mls blood in Lithium Heparin for tests requiring karyotyping.

Target Reporting times

Table 1

Method	Routine	Urgent
Whole genome sequencing	84 days	-
Whole exome sequencing	84 days	14-21 days
Sanger sequencing	42 days	3-14 days
SNP microarray	42 days	14 days
MLPA	42 days	3-14 days
Chromosome analysis	42 days	14 days
FISH	42 days	14 days
STR analysis	42 days	3-14 days
Carrier testing of known variant	42 days	3-14 days
Predictive testing of known variant	14 days	3 days

Updated 24/09/2024