Prader-Willi

Question 1

What chromosomal abnormalities cause PW?

Answer 1

A deletion of the q11-q13 region of chromosome 15 on the PATERNAL allele
…or maternal disomy

Question 2

Phenotype

Answer 2

Hypotonia
Characteristic facies (almond shaped eyes).
Undescended testicles
Severe feeding problems (need feeding tube)
Lighter pigmentation than rest of family
Ages of 2-4: feeding problems completely reverse
Child will eat everything (no satiation)
Pt becomes obese (treat w/ HGH)

Question 3

Medical problems

Answer 3

• Eyes: strabismus, nystagmus common
• Orthopedics: scoliosis is common
• Respiratory: obstructive sleep apnea may develop and is a contraindication to the use of growth hormone

Question 4

Developmental problems

Answer 4

mild-moderate cognitive disabilities are usually found, and behavioral issues are common.

Question 5

What other disorders are associated with chromosome 15?

Answer 5

Maternally inherited interstitial duplication of 15q: hypotonic, autistic, seizures. Same goes for IDIC (inverted duplicated isochromosome) 15

Question 6

15q duplications that are PATERNALLY derived will __________.

Answer 6

show a normal phenotype

Question 7

15q duplications that are MATERNALLY derived will ___________.

Answer 7

have partial trisomy as the phenotype and increased likelihood of autism