Basic genetics for ART practitioners

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.