14h45 brenda greyling
TRANSCRIPT
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Brenda GreylingGenetic Counsellor, MSc (Med)National Health Laboratory Service WITS
Introduction Genetic conditions
What is genetic counselling?
Who should be referred?
Cancer case examples
Genetic disorders common Contribute significantly to morbidity and mortality
2-5% of infants have > 1 congenital anomaly
1-2% of infants have a chromosome abnormality/single gene disorder
5-10% of adult population have a genetic disorder
Genetic disorders complex Team approach needed
Chromosomal disorders: Down syndrome
Single-gene disorders: haemophilia, albinism, NFI
Multifactorial disorders: cleft lip &/or palate
TRAUMA Spina bifida BRCA, HNPCC FAP
ENVIRONMENT MULTIFACTORIAL GENETIC
The process of helping people understand and adapt to themedical, psychological & familial implications of genetic
contributions to disease.
This process integrates:
Interpretation of family & medical histories to assess chance of disease occurrence/recurrence
Education inheritance, testing, management, prevention, resources & research
Counselling to promote informed choices & adaptation to the risk or condition.
Task force report: JGC 2 6
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Support
Educate
Facilitator
Respect
AutonomyAdv
ocate
Empower
Crisis
Team
Empathy
Individ
ualize
Decisio
ns
Pregnant women: advanced maternal age
positive screening test
teratogen-exposed
abnormality on sonar
abnormal result after prenatal testing
Couples family history of a known or suspected genetic
disorder
consanguineous
want testing or more information about geneticdisorders common in their ethnic group
had a previous child with chromosomal or geneticdisorder, birth defect or mental retardation
P
Individuals with: genetic disorder (Waardenburg syndrome)
birth defect (neural tube defect)
chromosomal disorder (Turner syndrome)
mental retardation or developmental delay
dysmorphic features (Treacher Collins)
Betty
25 years
Beatrice
29 years
Anna
45 yrs
Ca breast & ovary
HeatherDied 42 yrsCa breast
Jacob
55 yrs
Joy
Dx 24 yrs
Melanoma
Died 55 yrs
Ca breast
Key:
Breast & Ovarian cancer
Breast cancer
Melanoma
Ashkenazi Jewish descent Genetic counselling session I
High risk family
Bettys chance for BrCa ~ 40-50%
Genetic testing for BRCA genes
o 3 common muts in Ashkenazi Jews = 90% of families
o Need to test Anna 1st
o If mut found, then offer predictive testing to Betty
o If POS: high risk for BrCa (60-80%) & OvCa (20-60%)
o If NEG: pop risk BrCa
Management options for BRCA gene carriers
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Follow-up Anna attends GC & agrees to have testing
Mutation found in Anna & then Betty
Genetic counselling session II (result) 4/12 after initial session
Inform Betty that mut POS: breaking bad news
Discuss implications & options
Other at-risk relatives : sisterSimone
Died 15 yrs
Shadrack
Dx 10 yrs
Grace
7 yrsRichard
14yrs
Adele36 yrs
AbelDx 45 yrs
Jack40 yrs
MariaDied 60 yrs
Esther
18yrs
Key:
Colon cancer
Ben42 yrs
James39 yrs
Genetic counselling session I Disease features
o Cancer predisposition, 100s1000s precancerous
polyps develop
o AOO: avg 16 yrs (range: 7-36 yrs)
o By 35 yrs 95% have polyps
o Extracolonic cancers (small bowel, pancreas,
thyroid, CNS, liver)
Geneticso Autosomal dominant
oAPCgene
o Adele is obligate carrier ofAPCgene mutation
Genetic counselling session I Risk assessment
o 50% risk: Grace, Richard, Jack, Esther
Testingo Genetic testing offered to at-risk individuals
o Children included
Implications of havingAPCgene mutation
PLAN: blood taken from Richard for predictive
testing
Genetic counselling session II Richard tested NEG forAPCgene mut
Not at risk for colon cancer
NB: others still at risk
Mutation carriers:
o Colectomy
o Colonscopies from 10-12 yrs
o Other: liver u/s, AFP, thyroid
Donald Gordon Medical Centre Charlotte Maxeke Johannesburg Academic Hospital
Antenatal (157) & clinical (256)
Specialist clinics (haemophilia, CF, craniofacial, neurogenetic,metabolic)
C-H Baragwanath Hospital Rahima Moosa Women and Child Hospital Outreach
East London Port Elizabeth Polokwane, Limpopo, Tzaneen
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Division of Human GeneticsThe National Health Laboratory ServiceUniversity of the Witwatersrand, School of Pathology
Tel : (011) 489-9224/3Fax : (011) 489-9226