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Flashcards in Chromosome 15 disorders Deck (13)
1

Prader-Willi Syndrome results when genetic information is missing from the______.

paternal allele of 15q11-q13

2

3 ways to get PWD:

1. Deletion on paternal 2. Uniparental disomy 3. imprinting error

3

Testing?

Methylation test, then FISH or CMA to verify deletion.

4

Infant presenting with PWS may have?

Hypotonia, feeding issues (won't cry to feed, can't suck, often need G-tube), undescended testicles if male, hypopigmentation (pale and blonde)

5

Opthalmic concerns of PWS?

Nystagmus, strabismus

6

Orthopedic concerns of PWS?

Scoliosis

7

Respiratory concerns of PWS?

Obstructive sleep apnea. (contraindication to use of Growth Hormone)

8

Developmental concerns of PWS?

Late to walk, (3 years?), mild-moderate cognitive impairment, behavioral issues, hyperphagia

9

What gene is lost at the 15q11-q13?

deletion on the long arm of chromosome 15 (at 15q11-q13) on the paternally inherited homolog. This causes the loss of the SNORD116 snoRNA that is likely involved in mRNA processing

10

IDIC 15 inverted duplicated isodicentric 15q (supernumerary chromosome)

Full complement of 15, plus marker chromosome.

11

15q interstitial duplication

Inheritance from mom gives phenotype of AUTISM with no dysmorphic features, hypotonia, seizures. Inheritance from dad = nothing. (imprinted gene)

12

Angelman Syndrome, Phenotype:

mildly dysmorphic facial features which evolve with age, hypotonia in infancy progressing to spasticity in older patients, Intellectual Disability (ID), seizures, autism

13

4 ways to get Angelman:

1) Large deletion
2) Mutation in UBE 3A
3) UPD (paternal disomy)
4) Imprinting defect