Topic 5 Part 5 Genetic counseling

Question 1

Genetic counseling - definition

Answer 1

A gathering and exchange of information regarding the probabilities of various inherited diseases in an individual or in one’s offspring.

Question 2

Genetic counseling - purposes

Answer 2

1. To convey complex information to help people make life decisions.
2. To help families as they consider testing, when they receive the results, and in the weeks and months afterward.

Question 3

Genetic counselors are _ in providing psychological counseling to families.

Answer 3

Not formally trained (must provide referrals for issues such as grief, etc.).

Question 4

Psychosocial aspects of genetic counseling

Answer 4

1. Pregnancy termination of an affected fetus.
2. Gender diagnosis.
3. Reproductive rights - consanguinity, disabled, carriers.
4. Preimplantation genetic testing.
5. Presymptomatic testing or elective testing of children.

Question 5

The principal obstacles to effective genetic counseling are the counselor’s _

Answer 5

Emotional conflict(s) and incomplete knowledge base.

Question 6

Bioethical principles of genetic counseling

Answer 6

1. Patient autonomy - patients’ right to make decisions without any influence on the decision.
2. Nondirective counseling - technique that counsels on the necessary facts, alternatives and anticipated consequences without bias or coercion.
3. Informed consent - a legal condition or state of mind whereby the patient has the necessary understanding of the facts, implications and future consequences of an action in order to make a decision.

Question 7

To be credentialed as a genetic counselor, a person must complete a _

Answer 7

2-year master’s degree program.

Question 8

Four-step method of genetic counseling

Answer 8

1. Information gathering (pedigree, relevant testing, prior work-ups).
2. Diagnosis (M.D. involvement - accuracy is essential).
3. Information giving (medical implication, genetic implication - usually M.D. and genetic counselor together).
4. Support.

Question 9

Baseline risk

Answer 9

The risk for a genetic condition in the general population (e.g., the risk for Down syndrome is 1 in 800).

Question 10

Adjusted risk

Answer 10

A re-calculation of the baseline risk based on pertinent facts in the case (e.g., the risk for Down syndrome in the fetus of a 40-year-old woman is 1 in 100).

Question 11

Recurrence risk

Answer 11

The risk that a genetic condition already present in the family will occur again (e.g., the recurrence risk of CF for a couple who already has a child with cystic fibrosis is 1 in 4).

Question 12

A genetic counselor usually begins explaining risk factors for a genetic condition by discussing the _

Answer 12

Baseline risk.

Question 13

Information giving for a 18WGA pregnant woman who has a 4-times normal AFP level

Answer 13

1. The baseline risk for a neural tube defect is about 1 in 1000.
2. The adjusted risk for a neural tube defect in her fetus is about 1 in 250, based solely on the screening results.
3. 20% of “screen positive” results for NTDs are falsely positive.
4. Explanation of the sequelae of NTDs - paralysis, ambulation and continence issues.
5. Next steps: Do nothing, ultrasound for anatomy scan, amniocentesis for genetic analysis - carries a 0.5% risk for miscarriage.

Question 14

Information giving for a 10WGA 40-year-old pregnant woman referred for AMA

Answer 14

1. The woman’s fetus is at increased risk for chromosomal aneuploidy, especially Down syndrome.
2. The baseline risk for Down syndrome is about 1 in 800.
3. The adjusted risk for Down syndrome for a 40-year-old pregnant woman is about 1 in 100.
4. Explanation that this is a form of mental retardation and there is no treatment.
5. Next steps: Do nothing, ultrasound for anatomy scan, CVS (now) or amniocentesis (later) for genetic analysis.

Question 15

Nuchal thickness observed on ultrasound increases the risk for _ to 1 in 5.

Answer 15

Down syndrome.

Question 16

Information giving for a 37-year-old woman referred after breast cancer diagnoses in her mother (deceased) and 22-year-old sister (who has a detectable mutation in BRCA1)

Answer 16

1. The baseline risk for breast cancer is 1 in 9, with an average age of onset of 62.
2. The adjusted risk for breast cancer in this woman is as high as 1 in 2; if she carries the mutation, there is also a 1 in 2 risk with each pregnancy that she will transmit it.
3. The only “treatment” is a prophylactic mastectomy and hysterectomy.
4. Next steps: Do nothing, undergo presymptomatic testing.

Question 17

Information giving for a 9WGA 27-year-old pregnant woman with achondroplasia referred for genetic counseling

Answer 17

1. The baseline risk for achondroplasia is about 1 in 20,000.
2. The adjusted risk for achondroplasia in her fetus is about 1 in 2.
3. There is a 1 in 4 risk for miscarriage when both parents are affected.
4. Next steps: Do nothing, CVS (now) or amniocentesis (later) to look for FGFR3 mutation.

Question 18

The “do nothing” option requires that _

Answer 18

The patient has received complete information about all available options.