Rare Disease Scotland: progress report

2. Identifying And Preventing Rare Diseases (9 – 10)

2.1 The Scottish Screening Committee

The Scottish Screening Committee ( SSC) was established in 2016 to improve the strategic management of screening services in Scotland.

The primary objective of the SSC is to consider advice and recommendations which flow from the UK National Screening Committee ^[21] ( UK NSC) - an independent expert advisory group which advises Ministers and the NHS in the four UK countries about all aspects of screening. The role of the SSC is to consider UK NSC recommendations in the context of the specific Scottish circumstances.

Following Ministerial approval, the SSC nationally commissions the implementation of new screening programmes or changes to existing programmes and provides high level oversight of all development and performance in the Scottish screening programmes, based on reporting from National Services Division.

The SSC currently oversees six national screening programmes:

• Abdominal Aortic Aneurysm ( AAA) screening
• Bowel Cancer Screening
• Breast Cancer Screening
• Cervical Cancer Screening
• Pregnancy and Newborn Screening
• Diabetic Retinopathy Screening

With regards to rare diseases which are covered within the remit of the SSC, Newborn Blood Spot Screening ^[22] identifies babies who may have rare but serious conditions. The programme includes screening for:

• Sickle cell disease ( SCD)
• Cystic fibrosis ( CF)
• Congenital hypothyroidism ( CHT)
• Phenylketonuria ( PKU)
• Medium-chain acyl-CoA dehydrogenase deficiency ( MCADD)
• Maple Syrup Urine Disease ( MSUD)
• Isovaleric Acidaemia ( IVA)
• Glutaric Aciduria type 1 ( GA1)
• Homocystinuria ( HCU)

The UK NSC is currently assessing a number of other rare conditions that could potentially be included in the NHS Newborn Blood Spot Screening Programme. As with all screening programmes, these would only be introduced if it is clear that the benefits to newborn babies outweigh any potential harm.

2.2 Introduction of new screening tests

Following a review conducted by the UK NSC, the Scottish Government extended the Newborn Blood Spot Screening programme to test for Homocystinuria ( HCU), Maple Syrup Urine Disease ( MSUD), Glutaric Aciduria type 1 ( GA1), and Isovaleric Aciduria ( IVA) to all newborn babies up to one year old, extended from six months old.

The four additional conditions are very rare. They typically occur in between 1 in 100,000, and 1 in 200,000 births. In general, early dietary-based treatment for these conditions is effective. If untreated, babies with MSUD, IVA and GA1 can become suddenly and seriously ill, while symptoms of HCU can take up to one or two years to emerge.

Prior to the introduction of the new four tests, babies in Scotland were screened for Phenylketonuria ( PKU), Congenital hypothyroidism ( CHT), Sickle cell disease ( SCD), cystic fibrosis ( CF) and Medium-chain acyl-CoA dehydrogenase deficiency ( MCADD).

Since the new screening programme began on 20 March 2017, 20,748 babies have been tested, with 24 samples referred for either further testing or clinical referral.

2.3 UK Genetic Testing Network

The United Kingdom Genetics Testing Network ( UKGTN) ^[23] evaluates genetic tests for scientific validity and clinical utility to ensure that all tests undertaken by member laboratories are evidence based. The Scottish Genetics Laboratory Consortium Molecular and Cytogenetic laboratories ^[24] are currently members of the UKGTN, and as such can provide genetic services for the NHS throughout the UK. It is the expectation of commissioning arrangements, that Consortium laboratories (in relation to molecular genetics and cytogenetics) only undertake UKGTN (or for future nationally approved alternative) approved tests thus ensuring all tests undertaken are evidence based.

NHS England have recently taken over responsibility for the UKGTN. As part of the reconfiguration of NHS England genetic laboratories, a consultation on the future of the UKGTN evaluation process is anticipated in early 2018. In the meantime, NHS England is consulting with Scotland and other devolved nations on the best way forward.

There is currently no UKGTN equivalent body in respect of the evaluation of molecular pathology testing. Therefore, as part of the implementation of the nationally commissioned service, the Molecular Pathology Evaluation Panel ( MPEP) ^[25] was established to support the introduction of new tests and review and evaluate established tests. MPEP makes recommendations to the Molecular Pathology Consortium ^[26] on the clinical utility and validity of tests that should be provided on a national basis. This framework is based on UKGTN Test Evaluation Process and Scottish Medicines Consortium submission process.

NSD has established the Genetics Evaluation Panel for Scotland to complete the initial assessment of test requests (in anticipation of the changes to UKGTN), and to provide clinical advice to the Genetics Consortium on the most appropriate tests to be made available in Scotland.

To ensure appropriate carrier testing can be rolled out, examples of ongoing work to assess the clinical utility of carrier testing for patient groups are as follows:

BRCA testing in serious ovarian tumours

NHS Grampian launch the introduction of the somatic BRCA1/2 service; Testing of the genes BRCA1 and BRCA2 in individuals affected with breast/ovarian cancer and their family members has been available as a blood test in Scotland for a number of years. Finding a cancer causing sequence difference (mutation) in a patient’s blood (the germline) indicates future risks of developing additional cancers, is invaluable for guiding preventative treatments for members of the family and informs treatment options.

In particular, women with ovarian cancer who have a germline BRCA1/2 mutation can benefit from treatment with a new type of drug therapy called PARP inhibitors. Recent research has shown that even when a woman with ovarian cancer does not have a germline BRCA1/2 mutation detectable in her blood, if such an alteration is found in the tumour itself – an acquired ‘somatic’ BRCA1/2 mutation - she may benefit from treatment with PARP inhibitors. Due to the benefits described above, somatic BRCA1/2 testing is now available in Scotland for selected patients who might benefit from the test.

Primary Immune Deficiency ( PID) Genetic Service

Following discussions with the Scottish Paediatric and Adolescent Infection and Immunity Network ( SPAIIN) and agreement from NSD, a new service has been introduced in the Scottish Genetics Laboratory Consortium. The testing for PID is delivered by the Aberdeen Laboratory and aims to improve the treatment of children and young people with PID through the development of genetic testing. This testing will enable equity of access for Scottish patients to genetic testing, leading to improved diagnosis, care, and treatment.