Genetic Counseling...Why Genetic Counseling? 11/13/2017 33 13 million Americans have a genetic...

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Genetic Counseling

Brook Croke, M.S., M.P.H.Genetic Counselor, CooperGenomics

brook.croke@gmail.com

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

brook.croke@gmail.com

UIUC MCB Workshop SeriesNovember 13, 2017

Pioneers and Global Leaders Advancing Reproductive Genetics

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