Proposal form for the evaluation of a genetic test for NHS Service Gene Dossier Disease: Fetal sexing by non invasive prenatal diagnosis for serious X-linked conditions eg. Duchene muscular dystrophy (DMD) excluding haemophilia Test – Disease – Population Triad Disease – name OMIM number for disease Disease – alternative names please provide any alternative names you wish listed Disease – please provide a brief description of the disease characteristics Disease - mode of inheritance Gene – name(s) OMIM number for gene(s) Gene – alternative names please provide any alternative names you wish listed This dossier is presented for an assessment of a non invasive test for determination of fetal sex using cell free fetal DNA in the maternal c irculation as t he an alyte. S ex d etermination is u sed f or X-linked conditions (excluding haemophilia) or for disorders that manifest significantly different in one sex compared to the other. The s pecific c ondition r elevant t o t his do ssier i s t he X -linked condition D uchene m uscular dy strophy w hich r esults f rom mutations in the Dystrophin gene (OMIM + 310200). However, the information p rovided i n t his d ossier w ill ap ply t o al l ot her s erious X-linked di sorders w here f amilies s eek pr enatal di agnosis w ith a view to considering the termination of a pregnancy shown to be carrying a male fetus with the disease causing mutation on the X chromosome. Not applicable Not applicable DMD is a severe, progressive disease characterised by muscle weakness and leg contractures which leads to loss of walking and complete wheelchair dependence at around age 10. The most common cause of death is respiratory failure, although some die because of cardiac complications. The mean survival of patients with DMD in the UK is now 27 years of age. There is no curative treatment and life-long input into management is required. Other serious X-linked diseases carry risks of a variety of serious phenotypes, both physical and intellectual and to a degree that parents may seek to terminate affected pregnancies. Sex l imited i nheritance (presentation p redominantly or s olely i n one sex) due to X-linked loci. Analysis is carried out for the presence / absence of SRY gene sequence. *480000 Not applicable Gene – description(s) (including Locus tested SRY (Yp11.3) tested as single amplicon. number of amplicons). Approval Date: March 2011 Copyright UKGTN © 2011 Submitting Laboratory: GOSH, London 1 Mutational spectrum for which you Not applicable test including details of known common mutations. Real Time PCR Technical Method (s) The Real Time PCR assay has been extensively validated in house and is the most commonly employed technique worldwide for fetal sex determination using ffDNA. In addition to validation details provided below. Please see (Finning and Chitty 2008) which outlines details from the literature. Validation Process Note: please explain how this test has been validated for use in your laboratory From April 2007 to March 2009 189 pregnancies were tested in our laboratory for fetal gender for various indications. Results were validated by audit of pregnancy outcomes. Outcomes were obtained by audit and are available for 145 pregnancies. The outcomes of 44 pregnancies were not available due to miscarriage or loss to follow-up and could not be included in the validation. From April 2007 to March 2009, 40 pregnancies were tested for fetal gender due to risk of DMD. Pregnancy outcomes are known for 30 of these cases. Are you providing this test already? If yes, how many reports have you produced? Please give the number of mutation positive/negative samples you have reported For how long have you been providing this service? Is there specialised local clinical/research expertise for this disease? Are you testing for other genes/diseases closely allied to this one? Please give details From April 2007 to March 2009, 189 pregnancies were tested for fetal gender for various indications. 96 females, 84 males and 9 inconclusive results were reported. From April 2007 to March 2009, 40 pregnancies were tested for fetal gender due to risk of DMD. 23 females, 15 males and 2 inconclusive results were reported. Since 2006 Yes No Please provide details Dr A ngela B arnicoat is t he C linical u nit le ad f or t he North E ast Thames R egional G enetics S ervice. Research ad vice i s p rovided by Prof Lyn Chitty RAPID project UCL. Clinical r eferrals for D MD are m ade t hrough c linical g enetics and may be received via fetal medicine units. See care pathway. Yes. Sex determination for sex limited disorders such as congenital adrenal hyperplasia. 19 cases at risk of DMD were tested April 2007 – March 2008 Your Activity 21 cases at risk of DMD were tested April 2008 – March 2009 If applicable - How many tests d o y ou currently pr ovide annually i n your 189 index cases for various indications have been tested for fetal laboratory? gender from April 2007 – March 2009 Family members where mutation is known: not applicable Approval Date: March 2011 Copyright UKGTN © 2011 Submitting Laboratory: GOSH, London 2 25 cases for DMD per year within a total of 100 referrals for fetal Your Activity sex determination for all indications per year How many t ests w ill y ou b e able t o provide annually i n y our l aboratory i f this gene dossier is approved and recommended for NHS funding? Based on experience how many 70 cases for DMD per year within a total of 350 referrals for fetal tests will be required nationally (UK sex determination for all indications per year. wide)? This is based on the following data: In the 2008-09 C MGS audit a total of 350 f fDNA an alyses f or al l Please i dentify t he i nformation on indications were reported. which this is based Audit at 3 laboratoriesbetween 2007-09 identified136 ffDNA tests requested for DMD. CMGS audit data prior to the introduction of ffDNA tests: 2004-05 CMGS audit: 82 DMD prenatal tests 2005-06 CMGS audit: 64 DMD prenatal tests Fetal sex determination by NIPD is currently offered by two other National Activity UKGTN laboratories. (England, Scotland, Wales & Northern Ireland) If your l aboratory is unabl e t o p rovide the f ull national need please c ould y ou pr ovide information on ho w t he nat ional r equirement may be m et. For e xample, ar e you aw are of any ot her l abs ( UKGTN m embers or otherwise) offering this test to NHS patients on a l ocal ar ea bas is on ly? T his ques tion h as been included In order to gauge i f there could be any i ssues in equi ty of ac cess f or N HS patients. It i s appr eciated t hat some laboratories may not be abl e t o ans wer t his question. I f t his i s t he c ase p lease write “unknown”. Approval Date: March 2011 Regional Molecular Genetics Service – Manchester West Midlands Regional Genetics Laboratory – Birmingham Copyright UKGTN © 2011 Submitting Laboratory: GOSH, London 3 Epidemiology Estimated prevalence of disease in the general UK population Please identify the information on which this is based Estimated gene frequency (Carrier frequency or allele frequency) The prevalence of DMD is 1 in every 3500 live male births The overall birth frequency of X-linked recessive disease frequently leading to a request for PND in the UK is approximately 5.5 in 9,000* * from Population needs and Genetic Services 1993 HMSO Dd DH004322 6/93 Not applicable Please identify the information on which this is based Estimated penetrance Please identify the information on which this is based Not applicable Target Population This t est i s t argeted at w omen w hose p regnancies are at r isk of X-linked c onditions s uch as D MD but ex cluding haemophilia. These women will already have been seen, mainly by a clinical geneticist, an d s amples t aken f rom t he f amily t o i dentify t he disease c ausing m utations. O nce t he mutation i s i dentified families are informed and counselled with regard to implications including the availability of prenatal diagnosis. Once p regnant t hese w omen ar e r eferred f or N IPD u sually b y geneticists or g enetics c ounsellors. M any w ill b e s ent v ia a fetal medicine u nit as a d ating s can i s r equired ( regardless of h ow prenatal diagnosis is performed). Description of t he p opulation t o w hich this t est w ill a pply ( i.e. d escription o f the po pulation as d efined by t he minimum c riteria lis ted in t he t esting criteria) Estimated prevalence of disease in the target population Approval Date: March 2011 Women are accepted for testing where their pregnancies are at high r isk of an adverse outcome (generally 1 in 4) as c alculated from their family history. Copyright UKGTN © 2011 Submitting Laboratory: GOSH, London 4 Intended Use (Please use the questions in Annex A to inform your answers) X-linked recessive disorders causing disability/early death (example DMD) Please tick the relevant clinical purpose of testing YES NO Diagnosis  Treatment  Prognosis & Management  Presymptomatic testing  Risk Assessment for family members   Risk Assessment – prenatal testing Approval Date: March 2011 Copyright UKGTN © 2011 Submitting Laboratory: GOSH, London 5 Test Characteristics Analytical sensitivity and specificity This should be based on your own laboratory data for the specific test being applied for or the analytical sensitivity and specificity of the method/technique to be used in the case of a test yet to be set up. If more than one gene will be tested, please include your testing strategy and data on the expected proportions of positive results for each part of the process. Please illustrate this with a flow diagram. The p rotocol s tipulates t hat f etal g estation m ust be a m inimum of 7 w eeks by ul trasound s can f or t esting t o be c arried out. From 7-9 weeks gestation two separate maternal samples are analysed ( taken one w eek apart). After 9 w eeks g estation a single m aternal s ample i s an alysed. S amples ar e t ested f or t he presence of SRY (using CCR5 as an internal control), and a null result is reported female. The analytical s ensitivity an d s pecificity of t he R eal T ime P CR assay w as m easured i n 189 pr egnancies ( 394 t ests) over a period of 2 y ears from April 2007 to March 2009. When audited against pregnancy outcome there were 145 cases (including 30 DMD cases) with a known outcome and in these cases the test demonstrated 100% ( 95% C I 97. 5-99.9) concordance w ith no false positives or false negatives. For t hose 1 45 c ases w ith a k nown outcome (including 40 DMD cases) the sensitivity of the R eal Time PCR assay in this series is 100% ( 73/73) ( 95% C I 95.1%-99.9%) a nd t he s pecificity is 100% ( 72/72) ( 95% C I 95.0%-99.9%). This i s a chieved by testing two s eparate m aternal samples for the presence of SRY and b y stipulating that the fetus is at l east 7 weeks gestation at the time of sampling. We continue to audit all pregnancy outcomes. Clinical sensitivity and specificity of test in target population See above f or t he sensitivity an d s pecificity o f N IPD f or t he correct identification of either male or female sex. The clinical sensitivity of a test is the probability of a positive test result when disease is known to be present; the clinical specificity is the probability of a negative test result when disease is known to be absent. The denominator in this case is the number with the disease (for sensitivity) or the number without disease (for specificity) Clinical validity (positive and negative predictive value in the target population) The positive predictive value (prediction of a male fetus) which is 100% (73/(73+0) and the negative predictive value (prediction of a female fetus) which is 100% (72/(72+0)). The clinical validity of a genetic test is a measure of how well the test predicts the presence or absence of the phenotype, clinical disease or predisposition. It is measured by its positive predictive value (the probability of getting the disease given a positive Approval Date: March 2011 Copyright UKGTN © 2011 Submitting Laboratory: GOSH, London 6 test) and negative predictive value (the probability of not getting the disease given a negative test). Testing pathway Please include your testing strategy if more than one gene will be tested and data on the expected proportions of positive results for each part of the process. Please illustrate this with a flow diagram. This can be added to the document as a separate sheet if necessary. Clinical utility of test in target population (Please refer to Appendix A) For DMD and other X-linked recessive disorders causing disability/early death - referral to a tertiary c linical g enetics service f ollowing r ecognition of h igh g enetic r isk from a d iagnosis or a f amily h istory. C o-ordination of the NIPD p rocess and outcome f ollow –up is led by a clinical genetics unit. Pregnancies Please provide a description of the carrying male fetuses are then referred for invasive diagnostic clinical care pathway. testing for the specific condition. Please note that the care pathway prior to referral in pregnancy will be the same whether undergoing fetal sex determination using NIPD or whether undergoing traditional invasive testing. A cost c omparison between NIPD and invasive prenatal diagnosis has been led b y Prof Steve Morris, professor of h ealth ec onomics at UCL. Overall, differences in mean costs per pregnancy for NIPD ve rsus i nvasive p renatal d ianosis w ere s mall f or D MD (mean d ifference –£87, 95% CI -£303 to £131). Costs associated with N IPD w ere offset b y f ewer w omen r equiring i nvasive t esting. This i s b ased on t he c ost of N IPD as i t i s t oday. I f t he c ost of t he NIPD t ests ar e reduced savings w ill i ncrease. T his s tudy demonstrates that NIPD c an provide benefits for m any women by avoiding the risks of invasive testing, without incurring additional costs. How will the test add to the management of the patient or alter clinical outcome? Approval Date: March 2011 NIPD i n c ases of severe childhood onset c onditions ( e.g.DMD) is generally to avoid unnecessary invasive testing and improve the patient e xperience. Women c arrying a f emale f etus ( around 5 0%) do n ot r equire i nvasive t esting. T hose c arrying a m ale f etus require an i nvasive t est t o d etermine if the male f etus is af fected, information that allows parents the choice of terminating pregnancy. Thus w omen c arrying a female fetus c an avoid t he approx. 1% risk of miscarriage associated with the invasive test. Given that 350 NIPD tests for fetal sex d etermination were carried out i n 2007 -2009 t his avoided the loss of around 3 p otentially normal f etuses w hen c ompared t o i nvasive t esting. M any of t he women undergoing prenatal diagnosis because of a risk of Xlinked disorders will already have had an affected c hild and some will h ave already u ndergone t ermination o f p regnancy f or an Copyright UKGTN © 2011 Submitting Laboratory: GOSH, London 7 affected f etus. T hese p regnancies a re t herefore extremely precious and parents are understandably very keen to avoid the risk of losing a normal child secondary to an invasive test. Anecdotally, w omen under going N IPD r eport b enefits i n t erms of reduced anxiety compared to invasive testing. From April 2007 to March 2009, 40 pregnancies were tested for fetal ge nder due t o r isk of D MD. 23 f emales, 15 males a nd 2 inconclusive r esults w ere r eported. For t hose w here t he outcome is kn own, 15 w omen w ent o n t o h ave an i nvasive t est a nd 14 women did not have an invasive test. What impact will this test have on the NHS i.e. by removing the need for alternative management and/or investigations for this clinical population? NIPD r equiring a m aternal b lood s ample w ill r eplace t he n eed for an invasive diagnostic procedure requiring consultant expertise and time, use of ultrasound and other expensive equipment. NIPD requires only a maternal blood test. No i ncrease i n overall c aseload activity i s an ticipated t hrough t he adoption of t his p rocedure. N o i ncrease i n c ost t o t he N HS i s anticipated. The increase in Molecular G enetic ac tivity is offset by a reduction in Cytogenetic activity to prepare, culture and sex CVS / amnio samples. A h ealth ec onomics manuscript which i ncludes a d etailed evaluation of t he c osts t o t he N HS is summarised in clinical utility section What are the consequences of not doing this genetic test. Commissioners have asked for specific information to support introduction of tests. The alternative t o n on-invasive p renatal g ender d etermination would be for all w omen at risk of h aving a DMD baby t o und ergo invasive t esting ( CVS / Amnio) t o de termine s ex. T hese procedures each carry a risk of miscarriage. In 50% of cases invasive testing could be avoided if the pregnancy were previously demonstrated to be female by NIPD. Utility of test in the NHS In a couple of sentences explain the utility of this test for the disease(s) NIPD to determine fetal gender allows avoidance of an invasive test for DMD in pregnancies shown to be female. This removes the additional risk of miscarriage associated with such procedures. Is there an alternative means of diagnosis or prediction that does not involve molecular diagnosis? If so (and in particular if there is a biochemical test) please state the added advantage of the molecular test There is no alternative to NIPD at this early stage in pregnancy for fetal sex determination. Invasive diagnostic testing using CVS can only be done from 11 weeks gestation. In pregnancies at risk of severely disabling conditions prenatal diagnosis needs to be carried out as early as p ossible t o f acilitate parental c hoice of surgical t ermination of p regnancy ( <12 weeks g estation) i f appropriate. F urthermore C VS c arries a 1 % r isk of m iscarriage and so i f t his m ethod i s u sed i nevitably some u naffected pregnancies will be lost. Please describe any specific ethical, legal or social issues with this particular test? There a re n o ethical, l egal or s ocial i ssues w ith this ap plication of NIPD over and above those of c onventional prenatal diagnosis for sex l inked i ndications. N IPD f or f etal s ex d etermination is o nly carried out if a valid clinical indication is provided as outlined in the gene dossier. Referrals are only accepted from relevant clinicians. Please complete the testing criteria form. Approval Date: March 2011 Copyright UKGTN © 2011 Submitting Laboratory: GOSH, London 8 UKGTN Testing criteria Name of Disease(s): Fetal sexing by non invasive prenatal diagnosis for serious X-linked conditions eg. Duchene muscular dystrophy (DMD), excluding haemophilia Name of gene(s): not applicable Patient name: Date of birth: Patient postcode: NHS number: Name of referrer: Title/Position: Lab ID: Referrals will only be accepted from one of the following: Referrer Consultant in Fetal Medicine Consultant Clinical Geneticist Consultant Obstetrician Tick if this refers to you. Minimum criteria required for testing to be appropriate as stated in the Gene Dossier: Criteria Tick if this patient meets criteria Confirmation of a high risk to a pregnancy of serious X-linked disorder excluding haemophilia AND Testing performed after 7 weeks in pregnancy as confirmed by scan. A second sample will be required if test performed before 9 weeks If the sample does not fulfil the clinical criteria or you are not one of the specified types of referrer and you still feel that testing should be performed please contact the laboratory to discuss testing of the sample. Approval Date: March 2011 Copyright UKGTN © 2011 Submitting Laboratory: GOSH, London 9 GREAT ORMOND STREET CARE PATHWAY Fetal sexing by non invasive prenatal diagnosis for serious X-linked conditions eg. Duchene muscular dystrophy (DMD) excluding haemophilia 1. Woman a known carrier of an X-linked disorder eg DMD i i Additional information Red flag 2. Offer fetal sexing by NIPD i 3. Accept NIPD 5. Dating scan 4. Decline NIPD 6. Discuss options with parents i i 7. NIPD blood test (from 7 weeks) Sent to Regional Genetics Laboratory i 8. Invasive test (see 16) 9. Standard antenatal i care 7a. A second NIPD blood test is required one week later if the first is done before 9 weeks i 10. Male predicted 11. Female predicted 12. Inconclusive result 13. Offer invasive test 14. Confirm gender by ultrasound (from i 12 weeks) 15. Discuss options with parents i 16. Amniocentesis / chorionic villus sampling i 22. X-linked mutation absent 23. X-linked mutation present 25. Standard antenatal care i 26. Discuss options with parents i 17. Decline invasive test 18. Standard antenatal care i 19. Repeat NIPD (see 7) 20. Invasive test (see 16) 21. Standard antenatal care i 24. Standard antenatal care i 27. Refer as appropriate 10