Clinical Genetics

Question 1

sensitivity

Answer 1

frequency of a positive result when the disease is present (ability to detect affecteds) A/A+C

Question 2

specificity

Answer 2

frequency of negative result when disease is absent (ability to detect unaffecteds) B/B+D

Question 3

false positive

Answer 3

• test result is positive but person does not actually have disease
• B

Question 4

false negative

Answer 4

• test result is negative but person does have disease

- C

Question 5

positive predictive value

Answer 5

• the ability of a test to positively predict whether a person has a disease
• A/A+B i.e. true positives/(true positives plus false positives)

Question 6

negative predictive value

Answer 6

• ability of a test to predict accurately if a person does not have a disease
• C/C+D i.e. true negatives/(true negatives plus false negatives)

Question 7

Why should you screen for PKU? What is test sensitivity and specificity?

Answer 7

• Because if you detect it early, you can completely treat it
• high sensitivity, low specificity
• PPV 5%

Question 8

Why should you screen for Congenital hypothyroidism?

Answer 8

• to prevent ID and poor growth/development

- start thyroid treatment early and they should be okay