Download “Genetic counseling is a communication process which deals with




“Genetic counseling is a communication process which deals with the human problems
associated with the occurrence of risk or occurrence of a genetic disorder in a family.”
Genetic tests are routinely ordered and interpreted in primary care settings.
Obtaining and Interpreting a Family Medical Hx
o Most PCPs only spend 5 minutes or less on FHx
o A useful FHx allows PCP and pt to take action:
 Family planning
 Personalized medicine
 Disease prevention, delay disease expression, earlier diagnosis
 Genetic Therapy
 Ex. Angiofibroma anti-dimerization skin cream
o The pedigree
 The 4-generation pedigree is the genetic counselor’s primary tool that is
used for a genetic risk assessment.
 A proper pedigree can provide enough information for diagnosis when
genetic tests cannot be ordered or results are inconclusive.

A negative pedigree does not rule out hereditary risk
 Limited by (Neurofibromatosis good example*):
o Variable expressivity*
o Reduced penetrance (retinoblastoma)
o Limited family structure
 Smaller families, estranged relatives
o Genetic/allelic heterogeneity*
o Delayed age of onset
o Sex-limited expression
o Mosaicism/gonadal mosaicism*
o De novo mutations*
 Other complications
o Inbreeding, incest, adoption, non-parentage, egg/sperm
donors
o FHx red flags: F. GENES
 F – Family History
 G – Groups of congenital anomalies
 E – Extreme or exceptional presentation
of common conditions
 N – Neurodevelopmental delay or
degeneration
 E – Extreme or exceptional pathology
 S – Surprising laboratory values

Risk assessment
o Is this condition hereditary? What is the chance that X symptom will occur?
Establishing a diagnosis is essential to addressing these concerns.
o Qualification risk:
 diagnostic criteria met or not
 high, intermediate, or low risk
o Quantification risk:
 Bayesian analysis
 Empiric data
o Over 10,000 known genetic conditions (Online Mendelian Inheritance in Man http://www.omim.org/)
o SNPs are being marketed to physicians and consumers as having clinical utlility,
but often there is no study to back-up the claims and usually the data only applies
to European populations.
o We are currently in the age phenotype counseling. Test unaffected patient first,
then counsel about how to prevent disease phenotype.
o Genetic liability: lower the threshold for disease expression, the higher the
genetic liability
o Genotype + Environment = Phenotype
 Ex. DVT risk increased by Factor V leiden and OCT use

Ordering genetic tests
o Pre-test counseling
 Is the test needed
 Informed consent
o Tests
 Screening and diagnostic tests are complimentary.
 Screening: low or high
o Will require follow up
 Diagnosis: yes or no
 Testing may be DNA-based or not (e.g. biochemical serum screening,
IHC). DNA-based results are not necessarily diagnostic. Diagnosis may
not involve any form of testing if a physical exam is sufficient.
 Know the limitations of the test and the appropriate lab
o Post-test counseling (mutant vs variant)
 Positive (Pathogenic Variant)
 Is there an evidence-based management plan?
 Duty to warn at-risk relatives
 Negative (No Variant Detected)
 Do you have a negative management plan?
 Variant of Unknown Significance (VUS)
 Majority are benign
 Refer to research study


Psychosocial component of counseling
 Allow the patient to express how he/she feels about the risk,
people see these chances very differently. Use different methods
of explaining magnitude of risk and probabilities. Emphasize that
testing allows personalization of risk for each individual
Ethical, Legal, and social implications
o Most of what we perceive to be ethical dilemmas are really moral dilemmas.
Moral dilemmas occur when are not sure what is the right thing to do.
o Ethics is how we apply our morals in various situations—social ethics, family
ethics, legal ethics, medical ethics. So an ethical dilemma is when there are
conflicts between our stated ethical principles.
o Major moral dilemmas:
 Informed consent, duty to warn, gene patents, unexpected findings,
eugenics, abortion issues, wrongful birth, genetic discrimination, medical
futility, direct-to-consumer marketing of genetic tests, presymptomatic
testing of minors
o GINA: Genetic Information non-discrimination act
 Provides protections against discrimination by employers and health
insurers
 Does not cover life insurance, disability insurance, long-term care
insurance
 Those affected by discrimination may be eligible for the Pre-existing
Condition Insurance Plan (2011)