L22 Genetic Counselling Flashcards
FCC
Familial cancer centre
Genetic Risk assessment
- Interpretation of family and medical histories to assess the chance of disease occurrence or recurrence
- Facilitation of genetic testing as appropriate
Provision of information and advice
- education about inheritance, testing, management, prevention, resources and research
- cancer risk management and risk reduction advice
Counselling
- promote informed choices and adaptation to the risk or condition
- assess client’s own perception and interpretation of family history
- explore client’s response to the information
- psychosocial support and reassurance
Ongoing
- facilitation of family communication
- support for gene carriers
Most cancers are not inherited but all are genetic
- most cancers caused by accumulation of mutations in specific cells that alter growth/inhibit normal apoptosis and allow cells to spread uncontrollable
- mutations are somatic not germline
How cancer develops
see onenote
cancer tends to involve multiple mutations
Hereditary, familial and sporadic cancer
Hereditary - strongly acting single gene effect
Familial - some inherited component, possibly polygenic
Sporadic - mostly chance and/or environmental
Definitions of types of cancer
see onenote
Common forms of hereditary cancer
see onenote
e.g. hereditary breast and ovarian cancer, lynch syndrome, familial adenomatous polyposis (APC)
Risk assessment for breast/ovarian cancer
see onenote
Family history of breast/ovarian cancer can be used to estimate:
- person’s risk of developing these cancers
- probability of having an inherited mutation in a known cancer predisposing gene
Risk assessment and management guidelines
see onenote
What happens when a patient is referred to the FCC?
see onenote
Case study
see onenote
Things for a genetic counsellor to think about - risk assessment
see onenote
Assessment for genetic testing
see onenote
Likelihood of known gene mutation
- BOADICEA score
Pathology
Limited Family History
Other cancers
Ancestry
Risk assessment tools - BOADICEA
see onenote
Verification of cancers in families
see onenote slides
Send entire family tree to cancer council in Victoria
- Looks up everyone on
pedigree to give additional information
Cancer not reported but was verified to have cancer by the council (the relatives themselves didn’t know another family member had cancer) => changes BOADICEA calculations as new information was acquired
Types of genetic testing
see onenote
Mutation detection
Predictive testing
New BOADICEA
see onenote
Methods used for mutation detection
- next gen sequencing, also called massively parallel sequencing, to look at many genes at once
- sequencing = looking through the sequence to find small DNA changes or small indels
- can detect minor sequence variations as well as deletions/duplications
Generalised benefits of genetic testing
see onenote
6 points
Generalised risk of genetic testing
see onenote
11 points
Genetic testing process - practicalities
see onenote
blood sample and consent required from living affected individual
mutation detection
- performed using targeted gene panel
genetic counselling
- informed consent
- pros and cons
Outcomes of genetic testing
see onenote
- pathogenic mutation found
- likely pathogenic mutation found
- variant of unknown/uncertain significance
- polymorphism
- no mutation
Mutation identified in Annette - predictive testing available for family members
see onenote
Predictive testing
see onenote
For the genetic counsellor: what are some of the things she needs to think about?
e.g. insurance issues, possibility of passing on to children
Cancer risks for BRCA1 carrier
see onenote
Risk management strategies
see onenote
- surgical
- surveillance
- risk reducing medications
Some more issues to think about
see onenote
having kids tested, ethical issues associated with this
More genes associated with cancer risk
see onenote
Personalised medicine
- Everyone could get their risk profile; do they carry common but low risk alleles
Actionable incidental findings are common
see onenote
Rare cancer syndromes
see onenote
Hereditary diffuse gastric cancer
see onenote slides
- autosomal dominant
- gene: CDH1 (E-cadherin)
- majority of CDH1 related cancers occur before 40
