CGC Study Guide 2026
Everything you need to pass the CGC exam in one place: the exam format, every topic to study, real practice questions with explanations, flashcards, and full-length practice tests. Free, no sign-up needed.
CGC exam key facts
- The ABGC Certification Examination consists of 200 multiple-choice questions, of which 170 are scored and 30 are pre-test items. Source
- Candidates have four hours to complete the ABGC Certification Examination. Source
- The CGC exam is scored on a scale of 200 to 800, and the passing scaled score is 600. Source
- The ABGC Certification Examination for the CGC credential costs $675 for first-time applicants. Source
- ABGC does not limit the number of CGC exam attempts, but allows only one attempt during each test window. Source
- ABGC certification as a Certified Genetic Counselor is valid for five years. Source
📋 CGC Exam Format at a Glance
📚 CGC Topics to Study (24)
✍️ Sample CGC Questions & Answers
1. Which concept best explains the variable severity of mitochondrial disease among maternally related family members?
Heteroplasmy is the mix of mutant and normal mtDNA, and the proportion varies between cells and individuals, producing variable severity.
2. A pedigree shows an affected father who has no affected sons but all affected daughters. Which inheritance pattern is most likely?
Fathers pass their only X to all daughters and none to sons, so absent male-to-male transmission with all daughters affected indicates X-linked dominant inheritance.
3. Which of the following describes a mutation?
A mutation is defined as a change in the DNA sequence of an organism. These changes can range from a single nucleotide alteration to large-scale chromosomal rearrangements. Mutations can occur spontaneously or be induced by external factors, and they are the ultimate source of genetic variation, sometimes leading to disease or providing evolutionary advantage.
4. A patient asks about the difference between a 'screen positive' and a 'diagnostic positive' result for Down syndrome. The counselor correctly explains that:
Screening identifies individuals at increased risk who need diagnostic testing, while diagnostic testing provides definitive chromosomal confirmation.
5. Which condition is typically associated with autosomal recessive inheritance?
Cystic fibrosis is a classic example of an autosomal recessive condition.
6. Which law protects individuals from genetic discrimination in the U.S.?
The Genetic Information Nondiscrimination Act (GINA) prohibits misuse of genetic information.
🎯 Free CGC Practice Tests
📖 CGC Guides & Articles
What Practice Test Geeks adds beyond an AI chat for CGC
An AI chatbot can quiz you, but it can't reproduce the exam conditions or keep your record. Here you get:
- A timed, full-length CGC mock exam — 200 questions in 240 minutes with a 70% pass mark, modeled on the official exam's question count and time limit, followed by a score report broken down by exam domain.
- A fixed CGC question bank: the same test every attempt, so your score is comparable from one try to the next instead of changing with every regenerated quiz.
- Progress saved on your device: completed tests, scores and missed questions stay in My Progress, so you can retake only what you got wrong.
- A printable CGC cheat sheet you can print or save as a PDF.
- CGC flashcards built from the same question bank.
- Free CGC practice tests with the correct answer shown after each question.
How this page was made: written with AI tools and published by Nathan Beja, founder of Practice Test Geeks, who is responsible for its content. Exam facts are checked against the official sources listed below. Not reviewed by a subject-matter expert. Editorial policy
Sources & references
Exam facts on this page (fees, format, dates, passing scores) are checked against these official sources; the date is our last check. Editorial policy
- abgc.net — Test delivery, fees, exam format, registration deadline, retake fee, retake policy, test dates, time limit, eligibility, passing score · verified Nov 2026