Implication of new genetictechnologies on pre-pregnancyscreening and prenatal testing4th Annual Obstetric Malpractice Conf...
All couples hope for a healthy baby, however humanreproduction is hazardous• 4% of all babies are born with acongenital ab...
Wrongful birth litigation may occur following birth of a childwith a genetic disorder when1. A genetic risk was not identi...
Testing technologies andpractices relatively stable (andlimited) over last decade• Taking a family history• Down syndrome ...
Uptake of Down syndrome screening in Victoria© Copyright 2012, VCGS. 50100002000030000400005000060000700008000020002001200...
Three new genetic technologies will transform prenataldiagnosis over the next five years• Microarray• Next generation gene...
Microarray(molecular karyotype)
Next generation DNA sequencing• Currently able to sequence all genesin the body for approximately $2000(HGP cost was $3 bi...
Non invasive prenatal diagnosis (NIPD)• Using fetal DNA from maternalblood• Available in USA, China andHong Kong• Used as ...
Testing prior to pregnancy –Screening for autosomal recessive disease• AR diseases individually rare butcollectively commo...
Recessive genetic screening in AustraliaIn Australia, the main single geneconditions for which pre-pregnancygenetic carrie...
The ‘long tail’ of recessive genetic disease00.0050.010.0150.020.0250.030.0350.04CarrierfrequencyDisease frequency
‘Counsyl’ genetic test• Microarray-based approach• Just test for specific knownmutations• Cost $350-$500• Screens for 105 ...
New York Times January 29, 2010“Firm Brings Gene Tests to Masses”• A Silicon Valley start-up is making the bold claim that...
Next generation sequencing approach• Low cost (analytical cost $400)• Test whole sequence of 437 (ormore) genes• All peopl...
Testing in established pregnancies-Chromosome microarray in prenatal diagnosis• Introduced in Australia in 2011 but limite...
New genetic technologies present many new challenges• Testing capabilities have outstripped our ability to counsel andinte...
The future?© Copyright 2012, VCGS. 18
© Copyright 2012, VCGS. 19
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Implications of New Genetic Technologies on Pre-pregnancy Screening and Prenatal Testing

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Dr David Amor, Director, from Victoria Clinical Genetics Service has presented at the Obstetric Malpractice Conference. If you would like more information about the conference, please visit the website: http://bit.ly/10xh1iO

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Implications of New Genetic Technologies on Pre-pregnancy Screening and Prenatal Testing

  1. 1. Implication of new genetictechnologies on pre-pregnancyscreening and prenatal testing4th Annual Obstetric Malpractice ConferenceDavid Amor22nd June 2012VCGS is a not for profit subsidiary of Murdoch Childrens ResearchInstitute and the main provider of clinical and pathology geneticsservices in Victoria
  2. 2. All couples hope for a healthy baby, however humanreproduction is hazardous• 4% of all babies are born with acongenital abnormality or geneticdisorder that is evident at birth• Most people have at least onerecognised genetic disease• All people are born with a geneticpredisposition to various medicalproblems• Every genome contains 50-100variants that are expected to causegenetic disease© Copyright 2012, VCGS. 2
  3. 3. Wrongful birth litigation may occur following birth of a childwith a genetic disorder when1. A genetic risk was not identified prior to pregnancy2. A genetic disorder was not detected during the pregnancy© Copyright 2012, VCGS. 3Inheritance Able to detect at riskcouples prior to pregnancyAble to detect duringpregnancyInherited dominant + +New dominant - +Autosomal recessive + +X-linked + +Chromosomal +/- +Polygenic - +/-Epigenetic - +/-
  4. 4. Testing technologies andpractices relatively stable (andlimited) over last decade• Taking a family history• Down syndrome screening• CVS and amniocentesis• UltrasoundAllowing various reproductive options tobe exercised:• TOP• PGD• Not have children• Accept risk© Copyright 2012, VCGS. 4
  5. 5. Uptake of Down syndrome screening in Victoria© Copyright 2012, VCGS. 50100002000030000400005000060000700008000020002001200220032004200520062007200820092010NumberScreenedYearNBST1 MSST2 MSS
  6. 6. Three new genetic technologies will transform prenataldiagnosis over the next five years• Microarray• Next generation gene sequencingThese two technologies are transformative because they offer the ability tosimultaneously test for large numbers of genes in a cost effectivemanner• Non-invasive prenatal diagnosis (NIPD)© Copyright 2012, VCGS. 6
  7. 7. Microarray(molecular karyotype)
  8. 8. Next generation DNA sequencing• Currently able to sequence all genesin the body for approximately $2000(HGP cost was $3 billion)• Costs expected to be reduced to$100 per genome• Data storage and analysis areconsiderable problems
  9. 9. Non invasive prenatal diagnosis (NIPD)• Using fetal DNA from maternalblood• Available in USA, China andHong Kong• Used as screening test becauseaccuracy <100%• Cost $1000-$2000• Currently only capable ofdetecting DS and small number ofother abnormalities© Copyright 2012, VCGS. 9
  10. 10. Testing prior to pregnancy –Screening for autosomal recessive disease• AR diseases individually rare butcollectively common• >1000 known recessive genes(many more unknown)• All people have some recessivegenes• Many variants of uncertainsignificance
  11. 11. Recessive genetic screening in AustraliaIn Australia, the main single geneconditions for which pre-pregnancygenetic carrier screening is undertakenare:• Haemoglobinopathies(thalassaemia)• Autosomal recessive diseasesmore common in theAshkenazi Jewish communityincluding Tay-Sachs disease• Cystic fibrosis (conflictingguidelines and policy)
  12. 12. The ‘long tail’ of recessive genetic disease00.0050.010.0150.020.0250.030.0350.04CarrierfrequencyDisease frequency
  13. 13. ‘Counsyl’ genetic test• Microarray-based approach• Just test for specific knownmutations• Cost $350-$500• Screens for 105 diseases (mostlyrare)• Substantial risk of false negativeresults• Risk of false positive results• 1 in 4 people receive abnormalresult
  14. 14. New York Times January 29, 2010“Firm Brings Gene Tests to Masses”• A Silicon Valley start-up is making the bold claim that it can help eradicate more than 100 diseasesby alerting parents-to-be who have the carrier genes.• Counsyl is selling a test that it says can tell couples whether they are at risk of having children witha range of inherited diseases.• Once informed, couples can take steps like using IVF with genetic testing of embryos, to avoidbearing children who would have the diseases.“As a genetic counselor, I’ve been waiting for this for a really long time,”- Elena Ashkinadze genetic counselor.• But some experts say the company’s Web site overstates the case. The company calls its productthe Universal Genetic Test, for example, even though there are thousands of genetic diseases, notjust the 100 Counsyl tests detect.“Everyone hopes there is a test that will provide a perfect baby, but the reality is that that single magicbullet doesn’t exist,”- Dr. Joe Leigh Simpson, a geneticist and obstetrician.• Some experts say that such screening could save countless parents from heartache, and societyfrom the millions of dollars it can cost to care for even one severely ill person over a lifetime.• But some experts foresee new issues. So many people would be carriers for at least one diseasethat genetic counselors might be overloaded. Some critics, meanwhile, say such testing is a steptoward designer babies.
  15. 15. Next generation sequencing approach• Low cost (analytical cost $400)• Test whole sequence of 437 (ormore) genes• All people will receive abnormalresult therefore need to testboth partners• Interpretation of many resultsdifficult• Reliant on existing databasesthat are known to containinaccuracies© Copyright 2012, VCGS. 15
  16. 16. Testing in established pregnancies-Chromosome microarray in prenatal diagnosis• Introduced in Australia in 2011 but limited uptake todate• Expected to replace microscope analysis within 2years• Compared to microscope chromosome analysis, willdetect abnormalities in an additional• 1.7% pregnancy with normal ultrasound• 5.8% of pregnancies with abnormal ultrasound• Also will detect abnormalities of:• Unknown significance• Uncertain significance• Incidental findings© Copyright 2012, VCGS. 16
  17. 17. New genetic technologies present many new challenges• Testing capabilities have outstripped our ability to counsel andinterpret information• Pace of change is extremely rapid – when does a test become‘standard of care’ and how will this be judged retrospectively?• Multiple testing options replacing small numbers of mature tests• Informed choice and consent• Incidental findings and findings of uncertain significance• Multiple testing brings increased risks of false positive results and riskof terminating a healthy pregnancy• Interpretation of results is still evolving• No funding mechanisms in place• Insufficient resources for counselling• Ethical issues© Copyright 2012, VCGS. 17
  18. 18. The future?© Copyright 2012, VCGS. 18
  19. 19. © Copyright 2012, VCGS. 19

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