Transcript
Basic genetics for ART Basic genetics for ART practitionerspractitioners
Genetic CounsellingGenetic CounsellingAlison LashwoodAlison Lashwood
Centre for Genetics & PGD Guy’s Hospital, Centre for Genetics & PGD Guy’s Hospital, London.London.23.3.0723.3.07
Learning objectivesLearning objectives
Understand what genetic counselling Understand what genetic counselling is.is.
Awareness of specific issues affecting Awareness of specific issues affecting families with genetic disordersfamilies with genetic disorders
Review specific issues relating to PGDReview specific issues relating to PGD
What is “genetic What is “genetic counselling”?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)
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
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
Who may need genetic Who may need genetic counselling?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
Couples with recurrent miscarriages
Ethnic background indicates an increased genetic risk
Pregnant couples/individuals who fall into any of the above categories.
Roles in Genetic Roles in Genetic CounsellingCounselling
Genetic CounsellorGenetic Counsellor ‘‘Non-directive’ Provides
information Offers genetic tests Counsels Supports Offers follow-up
PatientPatient Makes the
decisions Lives with the
consequences
The consultationThe consultation
Case historyCase history
Ellie has cystic Ellie has cystic fibrosis- diagnosed fibrosis- diagnosed after birthafter birth
Sue & John had no Sue & John had no FH of CFFH of CF
Couple want to Couple want to have more childrenhave more children
Affected with CF
Affected with CF
Let the coupleLet the couple Tell their storyTell their story Ask what questions Ask what questions
they havethey have Acknowledge their Acknowledge their
feelings i.e. grief, feelings i.e. grief, anger etc.anger etc.
DiscussDiscuss Recurrence risksRecurrence risks Future optionsFuture options Other support?Other support?
Specific issuesSpecific issues
GriefGrief Impact on familyImpact on family Perception of riskPerception of risk
GriefGrief
Loss of health of selfLoss of health of self Loss of reproductive freedomLoss of reproductive freedom Loss of health of familyLoss of health of family GuiltGuilt FearFear
Impact on familyImpact on family
Affected with CF
Dee & Paul are 9/40 Dee & Paul are 9/40 pregnantpregnant
Different agendaDifferent agenda
- no/yes PND- no/yes PND
Differing viewsDiffering views
Impact of guilt- Impact of guilt- remember remember grandparentsgrandparents
John SuePaul
Dee
Risk perceptionRisk perception
Never attach your view of risk.Never attach your view of risk.
Family myths “it only happens to Family myths “it only happens to boys in our family”boys in our family”
Past experiencePast experience
You will never convince this You will never convince this family………family………
50% ???
Risk figures can be a difficult Risk figures can be a difficult conceptconcept
Present risk figures in different Present risk figures in different waysways
Present both positive and negativePresent both positive and negative
What do risks mean?What do risks mean?
20% 1%4:12/3
High or low?High or low?
1 in 2001 in 200 1 in 1001 in 100 1 in 101 in 10
20% or 1 in 520% or 1 in 5
1% or 1 in 1001% or 1 in 100
Difficult issues in genetic counselling
Confidentiality Late onset disorders Testing in pregnancy
ConfidentialityConfidentiality
Case historyCase history Donald has Becker Donald has Becker
muscular muscular dystrophydystrophy
XL inheritanceXL inheritance Daisy is an obligate Daisy is an obligate
carriercarrier Daisy is asking for Daisy is asking for
PGD to avoid PGD to avoid having an affected having an affected sonson
X Y
X X
X X
Neurologist informs me of AIDNeurologist informs me of AID Father does not want Daisy to know Father does not want Daisy to know
On testing Daisy is not a carrierOn testing Daisy is not a carrier
Outcome………………???Outcome………………???
Late-onset disorders and Late-onset disorders and presymptomatic testingpresymptomatic testing
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
45 years
19 years
21 years
Jo
Peter Beth
Implications of Implications of presymptomatic testingpresymptomatic 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
Genetic testing in Genetic testing in pregnancypregnancy
Genetic testing in Genetic testing in pregnancypregnancy
Impact of time frame for testing
Do couple understand implications of testing?
Is decision making compromised by emotion?
Potential for multiple bereavements
Case history
Homer and Marge-1st cousin partnership
No family history of note
Cystic fibrosis carriers
PND- affected fetus TOP
CF carrier
Marge
CF carrier
18/40
Homer
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
Genetic Counselling & PGDGenetic Counselling & PGD
PGD Genetic counselling offers a couple:PGD Genetic counselling offers a couple: An opportunity to review the genetics of the An opportunity to review the genetics of the
disorderdisorder Discuss reproductive options again.Discuss reproductive options again. Talk through their previous experienceTalk through their previous experience
PGD Genetic counselling offers a clinician:PGD Genetic counselling offers a clinician: A chance to clarify why the couple have A chance to clarify why the couple have
requested PGDrequested PGD Time for full discussion of the procedure Time for full discussion of the procedure
involved.involved.
Why couples request PGD?Why couples request PGD?
Prenatal diagnosis and TOP not Prenatal diagnosis and TOP not acceptableacceptable
Knowledge of having an unaffected Knowledge of having an unaffected child from conceptionchild from conception
Avoidance of further miscarriageAvoidance of further miscarriage Genetic disorder and fertility Genetic disorder and fertility
problemsproblems
Factors affecting requestFactors affecting request
Level of genetic riskLevel of genetic risk Previous experiencePrevious experience Expectation of successExpectation of success Perception of fertilityPerception of fertility
Level of genetic riskLevel of genetic risk
Paul affected with Paul affected with Duchenne Duchenne muscular dystrophymuscular dystrophy
Sally may have a Sally may have a 50% risk or a lower 50% risk or a lower 10% risk10% risk
Test looks for high Test looks for high and low risk X and low risk X chromosome only chromosome only
PGD may be more PGD may be more acceptable than acceptable than PND PND
Sally
Previous experiencePrevious experience
PND and TOP experiencePND and TOP experience
Health of affected childHealth of affected child
Death of affected child-timingDeath of affected child-timing
Belief in genetic riskBelief in genetic risk
Expectation of successExpectation of success
Do the couple understand the success Do the couple understand the success rate of PGDrate of PGD
Do the couple understand the impact Do the couple understand the impact of a PGD cycleof a PGD cycle
Limitations of PGDLimitations of PGD
PGD reduces risk rather than PGD reduces risk rather than eliminates iteliminates it
Perception of fertilityPerception of fertility
Delayed spontaneous conception Delayed spontaneous conception
Do the couple have concerns over Do the couple have concerns over their fertility?their fertility?
Recurrent miscarriage, is this due to Recurrent miscarriage, is this due to the chromosome abnormality?the chromosome abnormality?
Special issuesSpecial issues
Affect of PGD treatment on previous Affect of PGD treatment on previous childrenchildren
Welfare of the childWelfare of the child
Impact on affected childrenImpact on affected children
Case historyCase history Matt carries a Matt carries a
balanced reciprocal balanced reciprocal translocationtranslocation
Sophie has inherited Sophie has inherited an unbalanced versionan unbalanced version
Severe developmental Severe developmental delay and now on delay and now on dialysisdialysis
Potential impact of Potential impact of OHSS and multiple OHSS and multiple pregnancy.pregnancy.
18 months
Matt
Welfare of the childWelfare of the child
Case historyCase history Alex +ve HD gene Alex +ve HD gene
testtest Early signs presentEarly signs present Onset of HD likely to Onset of HD likely to
affect child care affect child care abilitiesabilities
Simon will be dual Simon will be dual carercarer
Impact of this on the Impact of this on the couplecouple
22 years
Early signs of
HD
42 yrs
Alex Simon
Genetic counselling after Genetic counselling after PGD cyclePGD cycle
Support if treatment unsuccessfulSupport if treatment unsuccessful Discussion around confirmatory Discussion around confirmatory
prenatal testing.prenatal testing. Confirmatory testing at delivery- Confirmatory testing at delivery-
conveying resultsconveying results Follow up of babies bornFollow up of babies born
In summaryIn summary
Genetic counselling is an important Genetic counselling is an important part of a clinical genetics service.part of a clinical genetics service.
It often raises complex issues for It often raises complex issues for both individuals and families.both individuals and families.
Many of the basic skills it employs Many of the basic skills it employs are transferable to other specialities.are transferable to other specialities.
PGD should include genetic PGD should include genetic counselling to meet the needs of a counselling to meet the needs of a good quality treatment programme.good quality treatment programme.
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