CBGC Genetic Counselling Certification (CCGC) flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Proband

The first affected family member who brings the family to medical attention; marked with an arrow on the pedigree and used as the starting point for family history collection.

Teach-back method

A communication technique in which the client explains the risk information and plan in their own words, allowing the counsellor to identify and correct misunderstandings.

Non-directive counselling

An approach that presents options neutrally and supports the client's autonomous decision without steering toward a particular choice, preserving reproductive and personal autonomy.

Informed consent elements

Disclosure of test purpose, limitations, possible results including uncertain findings, privacy and insurance implications, costs, and alternatives, followed by voluntary authorization.

Natural frequency framing

Presenting risk as counts out of a population, such as 25 of 100 pregnancies, which often improves comprehension compared with percentages or proportions in low-numeracy clients.

Autosomal dominant transmission

A pattern in which one pathogenic allele is sufficient to cause disease; an affected heterozygous parent has a 50 percent chance of transmitting the allele per pregnancy.

Autosomal recessive transmission

A pattern requiring two pathogenic alleles; carrier parents have a 25 percent chance of an affected child, 50 percent carrier, and 25 percent unaffected non-carrier per pregnancy.

X-linked recessive transmission

A pattern in which carrier females transmit to half of sons, who are affected, and half of daughters, who are carriers; affected males have no affected sons.

Bayesian risk calculation

A method that multiplies prior probability by conditional probabilities from test results or family data, then normalizes the products so revised risks sum to one.

Hardy-Weinberg carrier frequency

For a rare recessive allele, carrier frequency approximates 2q, where q is the square root of disease incidence in the population under equilibrium assumptions.

Mitochondrial inheritance

A pattern in which pathogenic mitochondrial DNA variants are transmitted maternally; offspring of affected males are unaffected, and severity varies with heteroplasmy.

Cell-free DNA screening

A maternal blood test analyzing placental DNA fragments to screen for common trisomies with high sensitivity; positive results require diagnostic confirmation by invasive testing.

Chorionic villus sampling

An invasive prenatal diagnostic procedure typically performed at 10 to 13 weeks that samples placental tissue and carries a small procedure-related miscarriage risk.

Amniocentesis

An invasive prenatal diagnostic procedure usually performed at 15 weeks or later that samples amniotic fluid and carries a small procedure-related miscarriage risk.

Residual carrier risk

The remaining chance a person carries a pathogenic variant after a negative carrier screen, calculated as prior risk multiplied by one minus the test detection rate.

Preimplantation genetic testing

Testing of embryos created through in vitro fertilization for monogenic conditions, structural rearrangements, or aneuploidy before embryo transfer.

BRCA1 and BRCA2

Genes in which pathogenic variants substantially increase lifetime breast and ovarian cancer risk and inform consideration of enhanced surveillance and risk-reducing surgery.

Lynch syndrome

A hereditary cancer syndrome caused by mismatch repair gene variants, increasing colorectal and endometrial cancer risk and identified through tumor screening and germline testing.

Somatic versus germline testing

Somatic testing examines tumor tissue for acquired changes; germline testing examines inherited DNA, and somatic findings may prompt germline confirmation when hereditary disease is possible.

Variant classification tiers

A five-category system of pathogenic, likely pathogenic, uncertain significance, likely benign, and benign that guides clinical interpretation and management decisions.

Chromosomal microarray

A test detecting copy-number gains and losses across the genome at higher resolution than karyotyping, commonly used for developmental delay and prenatal anomalies.

Analytical validity

The ability of a test to accurately and reliably measure the genetic variant it is designed to detect, including sensitivity, specificity, and reproducibility.

Clinical utility

The degree to which a test result improves health outcomes by changing management, informing reproductive decisions, or guiding surveillance and treatment.

Secondary findings

Medically actionable pathogenic variants unrelated to the primary testing indication that may be reported from genomic sequencing, with pretest discussion and opt-out options.

GINA protections

United States law prohibiting health insurers and employers from discriminating based on genetic information, but it does not cover life, disability, or long-term care insurance.

Duty to warn

The question of whether a counsellor may disclose genetic risk to at-risk relatives without client consent; disclosure generally requires permission, with limited jurisdiction-specific exceptions.

Decisional conflict

Uncertainty about a course of action accompanied by distress or perceived pressure, assessed and addressed through structured decision support and exploration of values.

Positive predictive value

The probability that a positive test result is truly positive, calculated from sensitivity, specificity, and pretest prevalence, which rises as prevalence increases.

Likelihood ratio

A ratio comparing the probability of a test result in affected versus unaffected individuals; values above one increase posttest probability and one indicates no change.

Evidence hierarchy

A ranking of study designs in which systematic reviews and randomized trials generally provide stronger evidence for intervention effects than cohort studies or expert opinion.

Pharmacogenomic testing

Testing of genes affecting drug metabolism or response to guide medication selection and dosing, interpreted with clinical guidelines before changing therapy.

Newborn screening follow-up

Coordination of confirmatory testing and specialist referral after an abnormal newborn screen, recognizing that false positives occur and require careful communication with families.