Chromosome 15 disorders Flashcards

1
Q

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

A

paternal allele of 15q11-q13

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2
Q

3 ways to get PWD:

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

Testing?

A

Methylation test, then FISH or CMA to verify deletion.

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4
Q

Infant presenting with PWS may have?

A

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

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5
Q

Opthalmic concerns of PWS?

A

Nystagmus, strabismus

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6
Q

Orthopedic concerns of PWS?

A

Scoliosis

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7
Q

Respiratory concerns of PWS?

A

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

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8
Q

Developmental concerns of PWS?

A

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

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9
Q

What gene is lost at the 15q11-q13?

A

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

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10
Q

IDIC 15 inverted duplicated isodicentric 15q (supernumerary chromosome)

A

Full complement of 15, plus marker chromosome.

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11
Q

15q interstitial duplication

A

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

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12
Q

Angelman Syndrome, Phenotype:

A

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

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13
Q

4 ways to get Angelman:

A

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

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