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The Primary Care Physician:The Primary Source
of Genetic Testing Information
Copyright University of Washington 2007
Imagine this…
Dr. Step is wrapping up the summer camp physical for his 10 year-old patient, Jay. He has addressed Jay’s
Warts Emerging myopia Safety counseling
Time is up.
Jay’s mother, Lisa, stands up to leave and says, “By the way, my husband, Tim, has just been diagnosed with colon cancer, and his doctors are calling it familial adenomatous polyposis. I heard there is a genetic test for FAP. Should Jay be tested?”
Genetic Counseling
• What is FAP and what causes it?
• Who else in the family could get FAP?
• Should we be tested for FAP?
• How can we cope with FAP?
• What kind of genetic test is it?
• How would the genetic test be used?
• Where can I find a lab that does the test?
• What is involved in ordering this genetic test?
• How can I answer all the questions that the
family has?
Genetic Testing
Where is Lisa going to go for an answer?
71% of American adults say they would most
likely ask their primary care physician about a
genetic disorder present in their family.
Genetic Testing: A study of consumer attitude AMA March 1998
Where is Dr. Step going to gofor answers?
A text book? Out of date
A journal? Highly focused
A colleague? Expertise varies
A Web site?
www.genetests.org
FUNDED BYNational Institutes of HealthContract No. N01-LM-3503
SPONSORING INSTITUTIONUniversity of WashingtonSeattle, WA
GeneReviews
• Genetic disease descriptions• >380 Reviews (April 2007)• One new Review added each week
• Expert-authored, peer-reviewed
• Current information on genetic test use in diagnosis, management, genetic counseling
• Links to genomic databases, patient resources, PubMed citations, policy statements/guidelines
International Laboratory Directory
615 Clinical and research laboratories 1370 Inherited diseases
• 1080 clinical tests• ~290 research only
Genetics and prenatal diagnosis clinics
• United States: ~ 1000 clinics
• International: ~ 100 clinics
Educational Materials
• Genetic counseling and testing concepts
• PowerPoint slide show presentations on genetic testing resources
• Illustrated Glossary of >220 terms
• Links to GeneticTools, a curriculum for teachers of primary care physicians
What is FAP and what causes it?
Who else in the family could get FAP?
Should we be tested for FAP?
How can we cope with FAP?
Genetic Counseling
Summary
Diagnosis
Clinical Description
Differential Diagnosis
Management
Genetic Counseling
Molecular Genetics
Resources
References
ACP-Associated Polyposis Conditions
Summary
Disease description• Colon cancer syndrome• Polyps develop 7-36 years• Colon cancer at 34-43 years
Diagnosis/testing
• Caused by mutations in APC• 95% of patients have identifiable APC mutations
Genetic counseling• Autosomal dominant
Clinical Description
• Colorectal adenomatous polyps: average 16 years
• Colon cancer: average 39 years
• Other features: osteomas, dental abnormalities, desmoid tumors
• Extra-colonic cancers (small bowel, stomach, pancreas thyroid, CNS, liver, bile ducts)
ACP-Associated Polyposis Conditions
What is FAP and what causes it?
Who else in the family could get FAP?
Should we be tested for FAP?
How can we cope with FAP?
Genetic Counseling
Genetic Counseling
Mode of Inheritance
• Autosomal dominant
Risk to Family Members
Parents of a proband.
• 75-80% of probands have an affected parent • 20-25% have a de novo mutation
Sibs of a proband. • If a parent has FAP, risk is 50% • If neither parent has FAP, risk is low
Offspring of a proband.
• 50% risk
ACP-Associated Polyposis Conditions
What is FAP and what causes it?
Who else in the family could get FAP?
Should we be tested for FAP?
How can we cope with FAP?
Genetic Counseling
Genetic Testing
What kind of genetic test is it? How would the genetic test be used? Where can I find a lab that does the test? What is involved in ordering this genetic test? How can I answer all the questions that the
family has?
Test Method Mutation Detection Rate Test Availability
Sequence analysis up to 90%
Mutation scanning and protein truncation ~80-~90% Clinicaltesting (PTT)
Protein truncation ~80%testing (PTT)
Duplication/deletion ~8-12%analysis
Molecular Genetic Testing
Direct DNA tests
Linkage
If no mutation is detected, linkage testing can be considered in families with more than one affected member.
ACP-Associated Polyposis Conditions
Genetic Testing
What kind of genetic test is it? How would the genetic test be used? How is the genetic test applied in this situation? What is involved in ordering this genetic test? How can I answer all the questions that the family has?
Management
Molecular genetic testing: By age 10-12 years
Surveillance: Persons with an APC mutation or at-risk for FAP who have not undergone molecular genetic testing:
• Annual sigmoidoscopy beginning at age 10-12 years
Colectomy: When polyps appear
ACP-Associated Polyposis Conditions
Management
Surveillance: Family members who have not inherited the disease-causing mutation:
• Routine colon cancer screening beginning at age 50 years
ACP-Associated Polyposis Conditions
Testing Strategy
Test Tim
Mutation detected• Direct testing useful• Proceed with testing family
• Direct testing not useful • Do not proceed with testing family
No mutation detected STOP
Genetic Testing
What kind of genetic test is it? How would the genetic test be used? Where can I find a lab that does the test? What is involved in ordering this genetic test? How can I answer all the questions that the
family has?
Genetic Testing
What kind of genetic test is it? How would the genetic test be used? Where can I find a lab that does the test? What is involved in ordering this genetic test? How can I answer all the questions that the
family has?
Ordering Genetic Testing
Genetic tests may be ordered by any physician.
• Choosing a laboratory• Pretest counseling and informed consent• Sample logistics and supporting documentation• Test result interpretation and follow-up
Genetic Testing
What kind of genetic test is it? How would the genetic test be used? Where can I find a lab that does the test? What is involved in ordering this genetic test? How can I answer all the questions that
the family has?
Genetics Consultation
A genetics consultation involves care of an individual or family to: Providing or arranging for psychosocial support
• Confirm, diagnose or rule out a genetic condition
• Identify / arrange for medical management
• Calculate and communicate genetic risks
• Provide or arrange psychosocial support
Medical Geneticists (MD, PhD)Certified by: American Board of Medical Genetics
Genetic Counselors (MS)Certified by: American Board of Genetic Counseling
and/or American Board of Medical Genetics
Genetics Professionals
Testing Strategy
Test Tim
Mutation detected• Direct testing useful• Proceed with
• genetic counseling• genetic testing of all at-risk relatives• surveillance of mutation-positive relatives only
Testing Strategy
Test Tim
• Direct testing not useful • Proceed with
No mutation detected STOP
• genetic counseling• surveillance of all at-risk relatives
FAPJay10 y
39 y 33 y 28 y
d. 35 y MVA
63 y
Indeterminant risk
Amy6 y
Sarah14 y
50% risk
Tim Lisa
AK MI TX
CA TN
What is FAP and what causes it?
Who else in the family could get FAP?
Should we be tested for FAP?
How can we cope with FAP?
Genetic Counseling
Roberta A Pagon, MD
Thomas D Bird, MD Cynthia R Dolan, MS Gerald L Feldman, MD, PhDRichard JH Smith, MD, PhDKaren Stephens, PhD
Suzanne B Cassidy, MDMary Beth P Dinulos, MD
Monica Smersh
Miriam Espeseth, MA
Carla Gifford
Editor-in-Chief
Associate Editors
Assistant Editors
Managing Editor
Online ProductionEditor
Editorial Assistant
Genetic Counselors
Laboratory DirectoryCoordinator
Clinic Directory Coordinator
Cynthia R Dolan, MSRoberta Spiro, MA
Gina McCullough Grohs
Aliya Hashemi
Database Administrator
SystemsAdministrator
Sergey Mikhaylov, MS
Brad Willson
Staff
GeneReviews
Principal Investigator Roberta A Pagon, MD
Directories
Technical Support
Resources
Resources Liaison Kathi Marymee, MS