Imprinting, PWS, and Angelmann

Question 1

Methyl CpG binding proteins are the proteins that bind to the methylated portion of the chromosome and affect gene expression. In a patient with Prader-Willi Syndrome, where would you expect these proteins to bind? What effect would this have on transcription?

Answer 1

Maternal chromosome- silence

Question 2

3 Characteristics of DNA Methylation

Answer 2

1. Formed in Gamete
2. Stable after fertilization
3. Reversible

Question 3

XX individual with del (15q11-q13) on maternal chromosome:

Answer 3

Angelmann’s Syndrome (S)

Severe learning disability
Seisures

Question 4

XY individual with del (15q11-q13) on paternal chromosome

Answer 4

Prader-Willi-

Hypotonia
Hypopigmentation
Hypogenitalism

*obesity

Question 5

Maternal uniparental disomy would result in:

Answer 5

Prader Willi.

PWS is the expression of ONLY maternal genes.

Question 6

Paternal uniparental disomy would result in:

Answer 6

Angelmann’s:

Comes from overexpression of PATERNAL genes.

Question 7

Why are CpG islands important?

Answer 7

They are the sites where Cytosine is methylated

Question 8

Patients with PWS are born with which features?

Answer 8

Hypotonic (floppy)
Dysmorphic (unusual) features
Impared mental development
Develop huge appetite

Question 9

Which genetic test is ordered to confirm a PWS diagnosis?

Answer 9

FISH or microarray if deletion is present.

Methylation tests are also used

Question 10

Maternally derived IDIC 15 (interstitial duplication) anomalies are associated with:

Answer 10

Non-dysmorphic Autism

Question 11

Paternal derived IDIC 15 (interstitial duplication) anomalies are associated with:

Answer 11

NO DISEASES