Requesting genetic testing

Click here to download the test request form*

*Before using this request form, please read the information below

Genetic tests typically requested by non-genetic specialists (e.g. GPs)

*Before requesting these tests, please check ECR to ensure that the patient has not been tested before. The results of these genetic tests will not change over time, and so repetition is of no value.

Alpha-1-antitrypsin deficiency

Alpha-1 antitrypsin deficiency (AATD) is one of the most common metabolic disorders in people of northern European heritage, with an estimated prevalence of ~1 in 2,000 – 5,000. The most common associated complications are chronic lung disease (e.g. emphysema and bronchiectasis) and liver dysfunction. AATD is an autosomal recessive disorder. It is estimated that ~1 in 20 of us are carriers of AATD. Carriers of AATD are not expected to be at an increased risk of liver or lung disease.

We do not see these patients in the Genetics clinic, unless there are additional issues.

Non-genetic specialists (including GPs) can request testing for AATD (4ml gold top blood sample, sent directly to Clinical Biochemistry). See also the Belfast Trust Lab User Manual.

* Before requesting this test, please check ECR to ensure that the patient has not been tested before. The results of these genetic tests will not change over time, and so repetition is of no value.

Cystic fibrosis

Cystic fibrosis (CF) has an estimated prevalence of ~1 in 3,000. The most common associated complications are chronic lung disease, exocrine pancreatic insufficiency and male infertility. CF is an autosomal recessive disorder. It is estimated that ~1 in 20 of us are carriers of CF. Being a carrier of CF is not expected to have any implications for your health, but it may have reproductive implications.

We do not see patients for CF carrier testing in the Genetics clinic, unless there are additional issues. Where both partners are found to be carriers of CF, the couple can be referred to Clinical Genetics to discuss reproductive options.

Non-genetic specialists (including GPs) can request CF carrier testing (5-10ml EDTA sample, sent to the Genetics lab). It is imperative to state the name and details of the patient’s known affected relative.

Click here to download the test request form.
* Before requesting this test, please check ECR to ensure that the patient has not been tested before. The results of these genetic tests will not change over time, and so repetition is of no value.

Haemochromatosis

Haemochromatosis is a common metabolic disorder in people of northern European heritage, with an estimated prevalence of ~1 in 500-1,000. The most common associated complications are liver cirrhosis, diabetes mellitus, joint pain and heart failure. Haemochromatosis is an autosomal recessive disorder. It is estimated that ~1 in 10 of us are carriers of haemochromatosis. Being a carrier of haemochromatosis is not expected to have any implications for your health. Further useful information can be found here: Haemochromatosis – NHS (www.nhs.uk)

We do not see patients for haemochromatosis carrier testing in the Genetics clinic, unless there are additional issues.

Non-genetic specialists (including GPs) can request haemochromatosis carrier testing (5-10ml EDTA sample, sent to the Genetics lab).

Acceptance criteria must be met and stated on the request form: (age ≥16years AND a diagnosis of haemochromatosis in a first degree relative (details of affected relative must be included) OR fasting transferrin saturation >55% in a male/postmenopausal female, OR fasting transferrin saturation >50% in a premenopausal female).

Click here to download the test request form.
*Before requesting this test, please check ECR to ensure that the patient has not been tested before. The results of these genetic tests will not change over time, and so repetition is of no value.

For patients identified as homozygous for C282Y or compound heterozygous for C282Y/H63D, further advice is available from local gastroenterology services, or Hepatology at RVH (if a Belfast Trust Area patient).

The Winton Centre for Risk and Evidence Communication provide some useful letter templates / patient information leaflets on various Haemochromatosis (HFE) results.

Genetic tests which are usually requested by a Clinical Genetics specialist only

For these more specialised genetic tests (e.g. gene panel tests, disease specific assays, neuro-predictive tests and whole exome or genome sequencing) please make a referral to Clinical Genetics.

In some circumstances, more specialised tests can be requested by non-Genetics specialists (“mainstreamers”). For these, please refer to the RMDS lab handbook.

Predictive genetic testing (patients at risk of inheriting a known familial variant)

Predictive genetic testing refers to testing undertaken in individuals who are known to be at risk of inheriting a familial genetic variant which predisposes to disease, but are themselves currently unaffected (e.g. a healthy individual with a known family history of a genetic variant in BRCA1/2, or an asymptomatic individual at risk of inheriting Huntington’s disease).

Patients must be referred to Clinical Genetics to discuss predictive genetic testing.

Please be aware that there is a three-appointment pathway established for neuro-predictive testing (e.g. Huntington’s disease, CADASIL, other hereditary dementias and hereditary motor neurone disease including C9orf72-related disorders).

For information on predictive genetic testing and insurance implications, please see information provided by Genetic Alliance and the Association of British Insurers.

Whole exome and genome sequencing

For further information on whole exome and genome sequencing please refer to the GENI section.

Other useful resources related to genetic testing

The National Genomic Test Directory – NHS England

The National Genomic Test Directory is a consensus document produced by NHS England. The Rare and inherited disease eligibility criteria document provides clinical criteria to help identify which patients are appropriate for a given genetic test. These criteria are revised and updated iteratively.

At present, the tests outlined in the genomic test directory do not map exactly to those which are available to patients in Northern Ireland. If you are in doubt, please contact GeneticsLabs@belfasttrust.hscni.net to discuss.

On the genetics test request form, it is helpful to state the relevant testing criteria, where possible.

PanelApp

PanelApp is a database that outlines the gene content of virtual gene panels (i.e. when exome or genome sequencing is undertaken, but the variant analysis is limited to only a portion of the genes which have grouped according to clinical presentation). These virtual panels are curated by expert consensus groups and revised iteratively. In general, only those genes labelled as “green genes” are actually included in the virtual panel.

At present, these PanelApp panels to do not match exactly with those listed in the genomic test directory, or the testing available in Northern Ireland, however they do provide a useful resource to identify potential genes of interest. On the genetics test request form, it is helpful to state specific genes of interest, where possible.

GeNotes: Genomic notes for clinicians

GeNotes (Genomic notes for clinicians) is an education resource being developed by Health Education England’s genomics education programme. It aims to provide clinicians with a guide for which patients are like to be eligible for genetic testing / a referral to Clinical Genetics. GeNotes also provides links to resources for extended learning.