Understanding Understanding Genetic Testing Genetic Testing Meron Azage, MS, CGC Certified Genetic Counselor
Jan 21, 2016
Understanding Understanding Genetic Testing Genetic Testing
Meron Azage, MS, CGCCertified Genetic Counselor
Learning ObjectivesLearning Objectives
Understand the role of the genetic counselor /geneticist
Review components of a genetic counseling session
Review basic genetic concepts Overview of types of genetic tests Review legal/ethical issues
The Role of the Geneticist The Role of the Geneticist • Physical exam • Generate a differential diagnosis• Order appropriate testing • Establish/ confirm a diagnosis–Not always possible
The Role of the Geneticist The Role of the Geneticist • Practice evidence-based medicine
- Recommend screening, management and treatments strategies
• Provide a referral to other specialists
• Apply ethical, legal, and social issue principles•Maintaining patient privacy
What is Genetic What is Genetic Counseling?Counseling?
“Genetic counseling is the process of helping people understand and adapt to the medical, psychological, and familial implications of genetic contributions to disease.”
NSGC 2005
What is Genetic What is Genetic Counseling?Counseling?Genetic counseling services span the life
cycle◦ From preconception counseling to
infertility evaluation◦ Prenatal genetic screening and diagnosis◦ Pediatric –Children with multiple birth defects or
developmental delay–Children with a known genetic conditions
◦ Predisposition evaluation and genetic diagnosis for a growing number of adult onset conditions.
What happens in a genetic What happens in a genetic counseling session?counseling session?Elicit medical history
Take family history
If a diagnosis is known, discuss natural history and inheritance of condition
Discuss relevant genetic testing◦ Offer testing to appropriate family members
Provide resources/ make necessary referrals
PedigreePedigreeDiagram that
records the family history information
An essential component of genetic counseling◦ They provide the
basis for making a diagnosis, determining risk, and assessing the needs for patient education and psychosocial support
Types of Inheritance Types of Inheritance PatternsPatternsChromosomalAutosomal DominantAutosomal RecessiveX-Linked Methylation defect MitochondrialDe NovoMultifactorial
Autosomal DominantAutosomal DominantAutosomal: genetic change is on
the autosomal chromosomesDominant: a change on one of
the chromosomes is enough to cause disease
Affects every generationAffects males and females
equally
AchondroplasiaAchondroplasiaChanges in the FGFR3 gene on
chromosome 4Short stature, enlarged head,
respiratory problems, ear infections
AchondroplasiaAchondroplasia
Types of Genetic TestingTypes of Genetic TestingClinical
◦Carrier testing◦Preimplantation testing◦Prenatal testing◦Newborn screening◦Diagnostic testing◦Predictive and presymptomatic
testingResearch
Clinical whole exome Clinical whole exome sequencingsequencingThe human exome is made up of all
the exons (functionally important parts of the gene translated into proteins).
The exome is less than 3% of the entire genome.
In the exome, about 85% of disease causing changes/ mutations happen.
This test looks at over 20,000 protein-coding genes.
What is the exome?What is the exome?
Genetic Counseling Code of Genetic Counseling Code of Ethics Ethics The counselor-client relationship
is based on values of care and respect for the client’s autonomy, individuality, welfare, and freedom.
Informed Consent Informed Consent Who is consenting?Are all the options presented?Does the patient understand the
options?Is the patient capable of giving
consent?
Genetic DiscriminationGenetic DiscriminationGINA is a law. Genetic testing results cannot be
used to discriminate by health insurance or employers◦Does not cover life, long term care or
disability insurance
ResourcesResourcesAmerican Board of Genetic Counselors
◦ Abgc.netNational Society of Genetic Counselors
◦ www.nsgc.orgNational Institute of Health – Genetic
Disorders◦ http://health.nih.gov/topic/
GeneticDisordersMy family health portrait
◦ https://familyhistory.hhs.gov/fhh-web/home.action
QUESTIONS ?QUESTIONS ?