Free medical quiz
Genetic Testing and Counselling Quiz
Focused SBA-style practice, followed by the answer and explanation for every question.
- Free now
- 5 questions
- Full bank
- 37 questions
- Answers
- Explained
Free question
Try one with the answer
A question from this quiz. Answer it to see the explanation students get.
A patient has unexplained muscle weakness and a clinician orders testing to establish its genetic cause. Which type of testing is this?
- A Predictive testing for a known familial muscle disease that may have caused the current weakness You picked ✕
- B Population screening for neuromuscular disorders in adults presenting with weakness You picked ✕
- C Pharmacogenomic testing to see whether the patient's weakness is an adverse effect of a prescribed medication You picked ✕
- D Carrier testing for a recessive muscle disorder to see whether the patient could pass the condition to their children You picked ✕
- E Diagnostic testing directed at the patient's current phenotype You picked ✓
Correct!
Incorrect
The answer is E: Diagnostic testing directed at the patient's current phenotype
Explanation
Why E is correct
See Diagnostic, Predictive and Carrier Testing. Option E is correct because this is diagnostic testing: the patient has relevant features now, and the test is ordered to explain them. The observable features of a patient are called the phenotype (here, the muscle weakness), and a diagnostic test looks for a genetic change that could account for it. Unexplained weakness in a person who is already unwell is the classic setting. It helps to remember that the four common test types are named by their purpose and not by the laboratory machinery: the same sequencing technology could be used to diagnose a child, to test a healthy relative, or to find a carrier. What changes is who is being tested, how likely the answer is beforehand, and what decision follows. The usual trap is to pick a test type because it sounds genetic, when the real question is whether the person tested is affected. A simple way to remember the purposes is to ask who is being tested and why:
- Diagnostic: a person with symptoms, to explain them
- Predictive: a healthy person, to see whether they inherited a known familial variant that raises future risk
- Carrier: a usually healthy person, to see whether they carry a recessive or X-linked variant that could affect their children
- Screening: a defined group of people, to estimate who has a higher chance and might need a diagnostic test
- Diagnostic testing: done in a person who has relevant features now, to explain them.
- Phenotype: the observable features, here the muscle weakness.
- Test type: named by its purpose (who is tested and why), not by the laboratory method.
Why the other options are incorrect
- A. Predictive testing for a known familial muscle disease that may have caused the current weakness: Predictive testing is for an unaffected person with a known familial variant to ask whether they will develop a disease, so it cannot be used to explain symptoms that are already present. Your answer
- B. Population screening for neuromuscular disorders in adults presenting with weakness: Screening offers a test to a defined group to estimate risk, but a patient presenting with symptoms is being investigated, not screened. The clinical indication makes this diagnostic testing. Your answer
- C. Pharmacogenomic testing to see whether the patient's weakness is an adverse effect of a prescribed medication: Pharmacogenomic testing guides drug choice or dosing based on genetic variation affecting drug response. It does not seek the cause of an existing disease such as unexplained muscle weakness. Your answer
- D. Carrier testing for a recessive muscle disorder to see whether the patient could pass the condition to their children: Carrier testing is used in a usually unaffected person to assess reproductive risk, not to explain symptoms in someone who is already affected. This patient has weakness and needs a diagnostic test. Your answer
With Premium, questions you miss become Revision Coach flashcards, scheduled for review.
Question preview
What you will practise
More questions from this set. Start the quiz to answer them and see each explanation.
-
1
A laboratory reports a variant of uncertain significance. What does this classification mean?
-
2
Why can chorionic villus sampling (CVS) or amniocentesis answer a different question from non-invasive prenatal testing (NIPT)?
Need wider coverage?
Explore every Genetics topic set, or build a tailored mixed session.
Browse subject quizzes