Quiz-summary
0 of 1 questions completed
Questions:
- 1
Information
USMLE Step 1 Questions
You have already completed the quiz before. Hence you can not start it again.
Quiz is loading...
You must sign in or sign up to start the quiz.
You have to finish following quiz, to start this quiz:
Results
Time has elapsed
You have reached 0 of 0 points, (0)
Categories
- Genetics 0%
-
Question:
A mother brings her two year-old son to your office because he has not yet spoken any words. On exam, he is very quiet, has a prominent jaw, large ears and large testicles. His mother states that she has a brother who is mentally retarded. Cytogenetic analysis reveals a genetic defect to be the cause of the patient’s mental retardation. What is the mostly likely mechanism of this genetic defect?
Correct Answer: D. Trinucleotide repeat
Fragile X syndrome is the most common cause of mental retardation in males. Key diagnostic factors are lack of milestone attainment, especially language, from a young age, large ears, large testes, a prominent jaw, a long face and flat feet. It is X-linked recessive inheritance that is caused by increased number of CGG repeats on the FMR1 gene. Normal CGG repeats are between 6 and 55, while Fragile X FMR1 alleles have over 230 repeats.
- 1
- Answered
- Review
-
Question 1 of 1
1. Question
Category: GeneticsA mother brings her two year-old son to your office because he has not yet spoken any words. On exam, he is very quiet, has a prominent jaw, large ears and large testicles. His mother states that she has a brother who is mentally retarded. Cytogenetic analysis reveals a genetic defect to be the cause of the patient’s mental retardation. What is the mostly likely mechanism of this genetic defect?
Correct
Incorrect