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Free CGC Practice Questions

10 free, exam-style Certified Genetic Counselor (CGC) practice questions with answers and explanations. No signup required. Work through them below, then take the full free CGC practice test to study every exam domain.

These 10 free CGC questions are organized by exam domain, so you can see how each part of the Certified Genetic Counselor blueprint is tested. Reveal the answer and explanation under each question.

Domain 1: Clinical Information, Human Development, and Genetic Conditions (34 questions / 20%)

Question 1

A 42-year-old woman is referred for genetic counseling after being diagnosed with endometrial cancer. Her family history reveals that her mother had colon cancer at age 48, a maternal uncle had urothelial carcinoma at 55, and a maternal grandmother had endometrial cancer at 52. Tumor testing of the patient's endometrial cancer shows microsatellite instability-high (MSI-H) and loss of MSH2 protein on immunohistochemistry. Which hereditary cancer syndrome is MOST consistent with these findings?

  1. Cowden syndrome (PTEN)
  2. Li-Fraumeni syndrome (TP53)
  3. Hereditary breast and ovarian cancer syndrome (BRCA1/2)
  4. Lynch syndrome
Show answer & explanation

Correct answer: D - Lynch syndrome

Question 2

A pregnant woman with epilepsy has been taking valproic acid throughout the first trimester. She is referred to genetic counseling at 10 weeks gestation. Which fetal anomaly is she at GREATEST risk for due to this exposure?

  1. Neural tube defect
  2. Ebstein anomaly
  3. Renal agenesis
  4. Limb reduction defects
Show answer & explanation

Correct answer: A - Neural tube defect

Domain 2: Risk Assessment and Principles of Human Genetics and Genomics (32 questions / 18.8%)

Question 3

A woman's brother has cystic fibrosis. Both parents are confirmed carriers. She has a negative result on a carrier screening panel that detects 90% of CFTR pathogenic variants in her ethnic group. What is her residual carrier risk?

  1. 1/4
  2. 1/6
  3. 1/30
  4. Essentially zero
Show answer & explanation

Correct answer: B - 1/6

Question 4

A 28-year-old man is diagnosed with myotonic dystrophy type 1 with a CTG repeat expansion of 180 repeats. His mother, who has mild myotonia and cataracts, has 90 repeats. His maternal grandfather was reportedly asymptomatic. This pattern of progressively earlier onset and increasing severity across generations is BEST explained by:

  1. Variable expressivity
  2. Reduced penetrance
  3. Germline mosaicism
  4. Anticipation due to trinucleotide repeat expansion
Show answer & explanation

Correct answer: D - Anticipation due to trinucleotide repeat expansion

Domain 3: Testing Interpretation, Testing Options, and Reproductive Risk Management (35 questions / 20.6%)

Question 5

A 3-year-old boy presents with global developmental delay, absent speech, and dysmorphic features. Standard karyotype is normal. The geneticist suspects a microdeletion syndrome. Which test is the MOST appropriate next step?

  1. Chromosomal microarray analysis
  2. Repeat karyotype with higher-resolution banding
  3. FISH for the 22q11.2 region
  4. Whole exome sequencing
Show answer & explanation

Correct answer: A - Chromosomal microarray analysis

Question 6

A 24-year-old woman with no significant family history has a positive cell-free DNA (cfDNA) screening result for trisomy 18 at 11 weeks gestation. She asks the genetic counselor whether her baby definitely has trisomy 18. Which response is MOST accurate?

  1. Given the high sensitivity of cfDNA, trisomy 18 is almost certain and she should prepare accordingly
  2. The result is likely a false positive caused by a laboratory error and she should repeat the cfDNA screen
  3. Diagnostic testing such as CVS or amniocentesis is needed to confirm, as cfDNA is a screening test
  4. Since she is young and low-risk, the cfDNA result is probably inaccurate and should be disregarded
Show answer & explanation

Correct answer: C - Diagnostic testing such as CVS or amniocentesis is needed to confirm, as cfDNA is a screening test

Question 7

A 45-year-old woman undergoes hereditary cancer panel testing, and a variant of uncertain significance (VUS) is identified in the PALB2 gene. She has a strong family history of breast cancer. Which is the MOST appropriate clinical recommendation?

  1. Base screening on her family history, not the VUS
  2. Proceed with risk-reducing bilateral mastectomy given the combination of family history and VUS
  3. Offer predictive testing for the VUS to her at-risk sisters
  4. Reclassify the variant as likely pathogenic based on family history
Show answer & explanation

Correct answer: A - Base screening on her family history, not the VUS

Domain 4: Counseling Skills, Communication, and Education (30 questions / 17.6%)

Question 8

A mother of a 5-year-old child with Down syndrome has been coping well overall. However, she becomes tearful when her child's kindergarten class performs at a school event, seeing the developmental gap between her child and peers. She reports that this sadness comes and goes, often triggered by milestones. She denies persistent depressive symptoms. This experience is BEST described as:

  1. Major depressive disorder
  2. Complicated grief reaction
  3. Chronic sorrow
  4. Adjustment disorder with depressed mood
Show answer & explanation

Correct answer: C - Chronic sorrow

Domain 5: Financial/Reimbursement Issues, Resources and Services for Clients, Legal and Regulatory Requirements, and Professional Frameworks (39 questions / 22.9%)

Question 9

A 35-year-old woman tests positive for a BRCA1 pathogenic variant. She is concerned about the impact on her insurance. Under the Genetic Information Nondiscrimination Act (GINA), which type of insurance is she NOT protected from discrimination?

  1. Employer-sponsored health insurance
  2. Life insurance
  3. Health insurance purchased through the ACA marketplace
  4. Group health insurance through her employer
Show answer & explanation

Correct answer: B - Life insurance

Question 10

A genetic counselor personally believes that termination of pregnancy is morally wrong. A couple receives a prenatal diagnosis of trisomy 13 and asks the counselor to discuss all available options, including termination. According to the NSGC Code of Ethics, the counselor should:

  1. Refer the couple to another counselor who can discuss termination
  2. Share their personal moral perspective to help inform the couple's decision
  3. Discuss only the options the counselor is comfortable presenting
  4. Discuss all reproductive options including termination in a non-directive manner
Show answer & explanation

Correct answer: D - Discuss all reproductive options including termination in a non-directive manner

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