Reducing Genetic Risk
Before, during and after pregnancy
Dr Neil Ginsberg
Paediatrician
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1859:
1866:
1953:
1972:
2001:
2013:
Darwin theory of evolution
Theory of genetics
DNA structure
DNA cloning
Human genome
Widely available gene testing
Evolution of Genetics
Diminishing risk
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Known risk
◦ Family history
◦ Advanced maternal age
◦ Exposure during pregnancy
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Unknown risk
◦ Unanticipated problems
Diminishing risk
Genes versus Environment
genetic
Cystic fibrosis
Thallasaemia
environmental
Hypertension
Heart disease
Diabetes
Asthma
Infections
Injuries
Before pregnancy
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Consider assessment if:
◦ Family history of an inherited condition
◦ Advanced maternal age (>35 years)
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Discuss with GP
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Referral to local genetic service
◦ Genetic counselling
 Information
 support
◦ Specific genetic testing
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Obtain as much info as possible
◦ How and when
◦ Advantages and disadvantages
◦ Risks to you or baby
◦ Any further testing
Things to consider before prenatal
testing
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Consider if abnormal
◦ What will the result mean for baby & family
◦ Options for further testing
◦ Your attitude to disabilities
◦ Your attitude towards termination
Things to consider before prenatal
testing
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Every cell: 46 chromosomes = 23 pairs
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Each pair contains:
◦ 1 from dad
◦ 1 from mum
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Chromosomes made up of multiple genes
Basics of Genetics
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Preimplantation Genetic Diagnosis
(PGD)
◦ Genetic at-risk babies
◦ Eggs are harvested from ovaries and fertilised
in the laboratory with sperm (IVF)
◦ One to two cells are removed from the embryo
at 3-5 days for testing
◦ Only normal embryos tested are transplanted
into the woman’s uterus
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Preimplantation Genetic Diagnosis
(PGD)
◦ In Australia only offered in the private setting
◦ High financial burden
◦ Emotionally stressful
◦ Answers question about specific conditions
During Pregnancy
Preimplantation
genetic
diagnosis
CVS
Nuchal
Non-invasive
translucency
prenatal
diagnosis
Amnio
Triple
2nd trimester
test
ultrasound
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Detection of a problem may require
further testing:
◦ Detailed US
◦ Specialised system US
◦ MRI
Ultrasound
Ultrasound
After Pregnancy
Performed on the entire population
Screening tests
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Paediatric clinical check
◦ Confirmation of normality
◦ Detect disorders not picked up antenatally:
 Hip dislocations
 Cardiac issues
 Eye problems
◦ Timing
 Day 1
 Prior to discharge
 6 weeks
Screening tests
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Hearing test (SWISH test)
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Newborn Screening Test
◦ Tests for chemical disorders
◦ Not otherwise detectable early
◦ Nearly all are easily managed
Screening tests
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Guided by antenatal findings or paediatric
check
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Kidney
Heart
Brain
Hips
Specific tests
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Be prepared
Establish family issues
Discuss with GP
Request referral if any concerns
Understand tests and consequences
Summary
Problems are uncommon
 Most pregnancies are normal
 Most babies are normal
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Summary