Page Contents
OVERVIEW
This page is dedicated to organizing various examples of standardized exam questions whose topic is phenylketonuria (PKU). While this may seem a odd practice, it is useful to see multiple examples of how PKU will be characterized on standardized exams (namely the boards and the shelf exams). This page is not meant to be used as a traditional question bank (as all of the answers will be the same), however seeing the classic “test” characterization for a topic is quite valuable.
KEY CHARACTERISTICS OF THIS CONDITION (ON EXAMS)
When it comes to standardized exams, each topic has its own “code” marked by key buzzwords, lab findings, clues, etc. If you are well versed in this code you will be able to more quickly identify the condition that is being discussed, and get the right answer on the exam you are taking. Below is the “code” for PKU.
- Intellectual disability
- Musty body odor
- Posture/gait abnormalities
- Eczema/light skin pigmentation
QUESTION EXAMPLES
Question # 1
Explanation # 1
Question # 2
Explanation # 2
TESTABLE FACTS ABOUT THIS TOPIC (BEYOND ITS IDENTIFICATION)
Many questions on standardized exams go beyond simply recognizing the underlying topic. Often there are specific testable facts regarding some aspect of the topic’s pathophysiology/management/clinical implications that are commonly asked. Some of these are listed below:
- Cause: classically caused by a deficiency of phenylalanine hydroxylase (enzyme responsible for converting phenylalanine to tyrosine). Tyrosine becomes an essential amino acid because it can not be made by the patient.
- Inheritance pattern: autosomal recessive
- Which amino acid accumulates: phenylalanine. Results in the production of phenyl acetate and phenyllactate (which cause symptoms like musty body odor)
- Treatment: restriction of phenylalanine intake.
Page Updated: 05.02.2017