Basic genetics for ART practitioners Genetic Counselling - PowerPoint PPT Presentation

Loading...

PPT – Basic genetics for ART practitioners Genetic Counselling PowerPoint presentation | free to view - id: 594bc-ZDc1Z



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Basic genetics for ART practitioners Genetic Counselling

Description:

Dee. Risk perception. Never attach your view of risk. ... Sophie has inherited an unbalanced version. Severe developmental delay and now on dialysis ... – PowerPoint PPT presentation

Number of Views:56
Avg rating:3.0/5.0
Slides: 43
Provided by: Alash
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Basic genetics for ART practitioners Genetic Counselling


1
Basic genetics for ART practitionersGenetic
Counselling
  • Alison Lashwood
  • Centre for Genetics PGD Guys Hospital, London.
  • 23.3.07

2
Learning objectives
  • Understand what genetic counselling is.
  • Awareness of specific issues affecting families
    with genetic disorders
  • Review specific issues relating to PGD

3
What is genetic counselling?
  • A communication process which deals with the
    human problems associated with the occurrence, or
    risk of occurrence, of a genetic disorder in a
    family.
  • (Ad Hoc Committee on Genetic Counselling,
  • American Society of Human Genetics, 1975)

4
It involves an attempt to help the individual or
family..
  • Comprehend the medical facts about a disorder
  • Appreciate the way in which heredity contributes
    to the disorder and to the risk of recurrence

5
  • Understand the options for dealing with the risk
    of recurrence
  • Choose the course of action which seems most
    appropriate to them
  • Make the best possible adjustment to the disorder
    in an affected family member

6
Who may need genetic counselling?
  • Those with a genetic condition
  • Those with a family history of a genetic
    condition
  • Parents with an affected child/pregnancy
  • Those who request a diagnostic opinion
  • Those in consanguineous partnerships

7
  • Couples with recurrent miscarriages
  • Ethnic background indicates an increased genetic
    risk
  • Pregnant couples/individuals who fall into any of
    the above categories.

8
Roles in Genetic Counselling
  • Genetic Counsellor
  • Non-directive 
  • Provides information
  • Offers genetic tests
  • Counsels
  • Supports
  • Offers follow-up
  •  
  • Patient
  • Makes the decisions
  • Lives with the consequences

9
The consultation
  • Case history
  • Ellie has cystic fibrosis- diagnosed after birth
  • Sue John had no FH of CF
  • Couple want to have more children

Affected with CF
10
  • Let the couple
  • Tell their story
  • Ask what questions they have
  • Acknowledge their feelings i.e. grief, anger etc.
  • Discuss
  • Recurrence risks
  • Future options
  • Other support?

Affected with CF
11
Specific issues
  • Grief
  • Impact on family
  • Perception of risk

12
Grief
  • Loss of health of self
  • Loss of reproductive freedom
  • Loss of health of family
  • Guilt
  • Fear

13
Impact on family
  • Dee Paul are 9/40 pregnant
  • Different agenda
  • - no/yes PND
  • Differing views
  • Impact of guilt- remember grandparents

Paul
John
Dee
Sue
Affected with CF
14
Risk perception
  • Never attach your view of risk.
  • Family myths it only happens to boys in our
    family
  • Past experience

15
You will never convince this family
50 ???
16
  • Risk figures can be a difficult concept
  • Present risk figures in different ways
  • Present both positive and negative

17
What do risks mean?
20 1 41 2/3
18
High or low?
  • 1 in 200
  • 1 in 100
  • 1 in 10

19
20 or 1 in 5
  • ??????
  • ??????
  • ??????
  • ??????
  • ??????

20
1 or 1 in 100
  • ????????????
  • ????????????
  • ????????????
  • ????????????
  • ????????????
  • ?????????????????
  • ?????????????????????

21
Difficult issues in genetic counselling
  • Confidentiality
  • Late onset disorders
  • Testing in pregnancy

22
Confidentiality
  • Case history
  • Donald has Becker muscular dystrophy
  • XL inheritance
  • Daisy is an obligate carrier
  • Daisy is asking for PGD to avoid having an
    affected son

X Y
X X
X X
23
  • Neurologist informs me of AID
  • Father does not want Daisy to know
  • On testing Daisy is not a carrier
  • Outcome???

24
Late-onset disorders and presymptomatic testing
25
Presymptomatic testing Case history
  • Jo has Huntington Disease
  • Beth and Peter at 50 risk
  • Both want to be tested
  • Outcome
  • Beth has ve test result
  • Peter has ve test result

Jo
45 years
Peter
Beth
19 years
21 years
26
Implications of presymptomatic testing
  • Impact of result when HD is an untreatable,
    incurable, late-onset genetic condition (e.g.
    HD)?
  • Social and psychological impact
  • Practical impact e.g., jobs, insurance
  • Survivor guilt

27
Genetic testing in pregnancy
28
Genetic testing in pregnancy
  • Impact of time frame for testing
  • Do couple understand implications of testing?
  • Is decision making compromised by emotion?
  • Potential for multiple bereavements

29
Case history
  • Homer and Marge-1st cousin partnership
  • No family history of note
  • Cystic fibrosis carriers
  • PND- affected fetus
  • TOP

Marge CF carrier
Homer
CF carrier
18/40
30
Issues
  • Request for reassurance
  • No previous knowledge of CF
  • Late stage of pregnancy urgency of making a
    decision
  • Loss of a much wanted pregnancy.
  • Confirmation of family fears

31
Genetic Counselling PGD
  • PGD Genetic counselling offers a couple
  • An opportunity to review the genetics of the
    disorder
  • Discuss reproductive options again.
  • Talk through their previous experience
  • PGD Genetic counselling offers a clinician
  • A chance to clarify why the couple have requested
    PGD
  • Time for full discussion of the procedure
    involved.

32
Why couples request PGD?
  • Prenatal diagnosis and TOP not acceptable
  • Knowledge of having an unaffected child from
    conception
  • Avoidance of further miscarriage
  • Genetic disorder and fertility problems

33
Factors affecting request
  • Level of genetic risk
  • Previous experience
  • Expectation of success
  • Perception of fertility

34
Level of genetic risk
  • Paul affected with Duchenne muscular dystrophy
  • Sally may have a 50 risk or a lower 10 risk
  • Test looks for high and low risk X chromosome
    only
  • PGD may be more acceptable than PND

Sally
35
Previous experience
  • PND and TOP experience
  • Health of affected child
  • Death of affected child-timing
  • Belief in genetic risk

36
Expectation of success
  • Do the couple understand the success rate of PGD
  • Do the couple understand the impact of a PGD
    cycle
  • Limitations of PGD
  • PGD reduces risk rather than eliminates it

37
Perception of fertility
  • Delayed spontaneous conception
  • Do the couple have concerns over their fertility?
  • Recurrent miscarriage, is this due to the
    chromosome abnormality?

38
Special issues
  • Affect of PGD treatment on previous children
  • Welfare of the child

39
Impact on affected children
  • Case history
  • Matt carries a balanced reciprocal translocation
  • Sophie has inherited an unbalanced version
  • Severe developmental delay and now on dialysis
  • Potential impact of OHSS and multiple pregnancy.

Matt
18 months
40
Welfare of the child
  • Case history
  • Alex ve HD gene test
  • Early signs present
  • Onset of HD likely to affect child care abilities
  • Simon will be dual carer
  • Impact of this on the couple

42 yrs
Alex
Simon
22 years Early signs of HD
41
Genetic counselling after PGD cycle
  • Support if treatment unsuccessful
  • Discussion around confirmatory prenatal testing.
  • Confirmatory testing at delivery- conveying
    results
  • Follow up of babies born

42
In summary
  • Genetic counselling is an important part of a
    clinical genetics service.
  • It often raises complex issues for both
    individuals and families.
  • Many of the basic skills it employs are
    transferable to other specialities.
  • PGD should include genetic counselling to meet
    the needs of a good quality treatment programme.
About PowerShow.com