Hy Review Usmle Step 1: Biochemistry (D10)

Front 1

What is an example of codominance?

Back 1

Blood groups

Front 2

Not all individuals with a mutant genotype will show the mutant phenotype. This is known as...

Back 2

Incomplete penetrance i.e. generation skipping

Front 3

Differences in phenotype depend on whether the mutation is of maternal or paternal origin. This is known as...
Give an example of a condition.

Back 3

Imprinting
Prader-Willi (paternal deletion) and Angelman's Syndrome (maternal deletion)
*both conditions are due to inactivation/deletion of genes on Chr.15

Front 4

Mental retardation, trying to eat everything, short and fat
(+) hypogonadism, hypotonia

Back 4

Prader-Willi syndrome (MR, hyperphagia, short stature due to GH deficit, obesity, hypogonadism and hypotonia)

Front 5

Mental retardation, seizures, ataxia, loves to laugh at inappropriate times

Back 5

Angelman's Syndrome

Front 6

Severity of disease worsens or age of onset of disease is earlier in succeeding generations i.e. Huntington's disease. What genetic phenomenon is this?

Back 6

Anticipation

Front 7

Occurs when cell in the body have different genetic makeup. What is this and give an example

Back 7

Mosicism
Ex: Lyonization (random X inactivation in females)

Front 8

p^2 + 2pq + q^2 =1

Back 8

Disease Prevalence

Front 9

p+q =1

Back 9

Allele prevalence

Front 10

2pq

Back 10

heterozygote prevalence