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11/13/2017 1
Genetic Counseling
Brook Croke, M.S., M.P.H.Genetic Counselor, CooperGenomics
UIUC MCB Workshop SeriesNovember 13, 2017
OVERVIEW
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EVALUATING GENETIC RISK
GENETICS OF HUMAN DISEASE
THE PATH TO GENETIC COUNSELING
CELL ANATOMY
CHROMOSOMES ARE INSIDE THE NUCLEUS OF OUR CELLS
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CHROMOSOME STRUCTURE
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ONE CHROMOSOME BEFORE REPLICATION
ONE CHROMOSOME AFTER REPLICATION
Centromere Centromere
“p” Arm “p” Arm
“q” Arm“q” Arm
Two Identical Sister Chromatids
DNA STORAGE
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Genes within our DNA provide the instructions for the body to create proteins.Proteins help our body grow, function, and repair itself.
GENETICS OF HUMAN DISEASE
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MUTATIONS ARE CHANGES IN GENES
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Mutations can be passed down from parents or they can happen sporadically.
SOME MUTATIONS MAKE US UNIQUE
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Humans are >99% alike. The remaining ~1% is what makes us each unique. Mutations in some genes lead to differences in traits like hair and eye color. However, some mutations can cause genetic disease.
TYPES OF GENETIC DISEASE
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Multifactorial Condition
+
Single-gene Disorder
Chromosome Abnormality
X X Y
AUTOSOMAL DOMINANT INHERITANCE
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AUTOSOMAL RECESSIVE INHERITANCE
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X-LINKED INHERITANCE
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TYPES OF GENETIC DISEASE
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Multifactorial Condition
+
Single-gene Disorder
Chromosome Abnormality
X X Y
TYPES OF GENETIC DISEASE
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Variations of chromosomal
material
Chromosome Abnormality
X X Y
NONDISJUNCTION
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Normal Meiosis I
Normal Meiosis II
Nondisjunction in Meiosis II
Oocytes containing the correct number of chromosomes
Oocytes containing the incorrect number of chromosomes
MONOSOMY
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TRISOMY
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TRIPLOIDY
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COPY NUMBER VARIATION (CNV)
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1 copyNormal
0 copiesAbnormal
2 copiesAbnormal
RECIPROCAL TRANSLOCATION
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ROBERTSONIAN TRANSLOCATION
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NORMAL NONHOMOLOGOUS, ACROCENTRIC CHROMOSOMES
ROBERTSONIAN TRANSLOCATION
Breakage and Rejoining
INVERSION
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PARACENTRIC INVERSION(Does not include centromere)
PERICENTRIC INVERSION(Includes centromere)
TYPES OF GENETIC DISEASE
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Multifactorial Condition
+
Single-gene Disorder
Chromosome Abnormality
X X Y
MULTIFACTORIAL CONDITIONS
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+
GENOTYPE TO PHENOTYPE
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PenetranceHow often a genotype correlates to a phenotype
Variable ExpressivityThe same condition has differing
symptoms & severity in different people
X-inactivationRandom inactivation of one
X chromosome in each cell
MosaicismGenetic makeup varies among cells
MOSAICISM
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CELL DIVISIONMOSAIC TISSUE
NORMAL CELLS
CELLS WITH GENETIC CHANGE
EVALUATING GENETIC RISK
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FAMILY HISTORY
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EMPIRIC RISKS: SCHIZOPHRENIA
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General Population Risk of Schizophrenia: ~1%
Your risk is increased if you have a family member affected with schizophrenia.
Affected Relative Recurrence Risk (%)
Sibling 7 - 10
Both Parents 45
One Parent 7 - 16
Identical Twin 40 - 50
Fraternal Twin 10 - 18
First Cousin 1 - 2
Data from: Harper PS. Practical Genetic Counseling. 7th ed. Boca Raton: CRC Press; 2010. and March of Dimes. Empiric recurrence risks for common multifactorial conditions. Genetics & Your Practice.
ENVIRONMENTAL RISKS
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Advanced Maternal &
Paternal Age (AMA & APA)
Teratogens
THE PATH TO GENETIC COUNSELING
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Why Genetic Counseling?
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13 million Americans have a genetic disorder
10% of chronic diseases, such as heart conditions, cancer, diabetes, and arthritis, have a significant genetic component
31% of the time, physicians misinterpret results of genetic testing (NEJM 1997. 336(12):823--‐7)
Is this the right career for you?
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Genetic counselors work in a variety of settings
Room for movement within the field
There is flexibility in work schedule (work from home options becoming more common)
Patient interaction whether in clinic or working in a laboratory setting
My Experiences
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• Private laboratory (CooperGenomics, NxGen MDx)
• University clinics (SIUSOM, UICOMP)
• Illinois Department of Public Health – Newborn Screening Program
• Blog writer – ataxic CP, radiation
Graduate Programs
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Almost 40 genetic counseling graduateprograms in the US and Canada
Several new programs under review, online program starting next Fall. Number of students matriculating in 2016(including Canadian schools): 317
No additional clinical training, residency etc., go directly into the job market following graduation from ~2 yr. program
Applying
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• 3 letters of recommendation• GRE scores• Shadowing GCs• Volunteer experience (crisis counseling, hospice,
special olympics, etc.)
Preparing for the interview
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• Become familiar with hot topics in genetics• https://www.cdc.gov/genomics/update/current.htm• Familiarize yourself with health care laws surrounding
genetics (GINA, state laws surrounding NBS)• Take a look at 23andme website (good intro to• direct to consumer testing)• National Society of Genetic Counselors (NSGC)• Genetic Task Force of Illinois (GTFI)
SUMMARY
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• Our understanding of molecular genetics has rapidly increased and molecular genetics is becoming an increasingly relevant and integral part of reproductive medicine
• Genetic counseling may be the right career for you!
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Thanks for attending!
Brook Croke, M.S., M.P.H.Genetic Counselor, CooperGenomics
UIUC MCB Workshop SeriesNovember 13, 2017
Pioneers and Global Leaders Advancing Reproductive Genetics
© 2017 CooperSurgical, Inc. All Rights Reserved.
