Prader Willi Syndrome

Question 1

A genetic evaluation in Prader Willi (PWS) will include a _________ karyotype.

Answer 1

Normal

Question 2

A FISH test for PWS will test ______ for deletion of Chr __________.

Answer 2

positive; 15q11-q13

Question 3

During preschool age, feeding difficulties in children w/ PWS will _______.

Answer 3

Reverse; the children will then develop hyperphagia and gain weight.

Question 4

PWS results when genetic info is missing from the (paternal or maternal) allele of Chr________.

Answer 4

Paternal; 15q11-q13

Question 5

PWS may result because: (3 reasons)

Answer 5

1. deletion of paternal allele; 2. uniparental disomy (2 copies present from only mom); 3. Imprinting error in how alleles are marked, causing virtual maternal UPD (leadingbody to think that Chr is missing.

Question 6

A deletion in the maternal allele in 15q results in what disorder?

Answer 6

Angelman syndrome

Question 7

Other problems associated with Chr 15q?

Answer 7

Maternally inherited 15 q interstitial duplication, isodicentric isochromosome 15q (IDIC 15), Marker chromosomes (inverted duplication), deletions (Angelman Syndrome)

Question 8

The maternal and paternal alleles are marked by different patterns of _________.

Answer 8

Methylation

Question 9

Testing for PWS

Answer 9

1. Methylation testing of Chr 15 for deletion; 2. If deletion present; a FISH test or a microarray can be done to confirm diagnosis.

Question 10

Infancy PWS Characteristics

Answer 10

Hypotonicity, almond shape eyes, undescended testicles, severe feeding problems (need Gtube), lighter pigmentation than family members.

Question 11

Toddler/Preschooler PWS Characteristics

Answer 11

Usually btwn ages 2-4, feeding problem reverses, become obese b/c don?t ever feel sated unless treated with growth hormone

Question 12

Eye Medical Issues in PWS

Answer 12

Strabismus (lazy eye), and Nystagmus (jiggly eyes)

Question 13

Orthopedics Medical Issue in PWS

Answer 13

Scoliosis

Question 14

Respiratory Medical Issue in PWS

Answer 14

Obstructive Sleep Apnea (contraindication to use of growth hormone)

Question 15

Developmental Issues in PWS

Answer 15

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

Question 16

It has been reported that a linkage disequilibrium between pts with Autism and Polymorphisms occurs in ________ locus on Chr 15.

Answer 16

GABAa-b3

Question 17

gamma-aminobutyric acid type A is an important ______ in the CNS, and is synthesized from the GABAa-b3 locus.

Answer 17

neurotransmitter

Question 18

What chromosome anomaly is one of the most frequently reported cytogenic abnormalities in patients with Autism?

Answer 18

Maternally derived proximal 15q11-q13 (supernumerary marker Chr, IDIC 15)

Question 19

What are the phenotypes in pts with Chr anomaly, Inverted Duplicated Isocentric 15q (IDIC 15)?

Answer 19

Autism, NOT dysmorphic, often hypotonic, seizures common

Question 20

15q interstitial duplication can result in what anomaly?

Answer 20

partial Trisomy

Question 21

The 15q interstitial duplication of 15q does NOT have a phenotype if it is inherited from the _______.

Answer 21

father

Question 22

Maternally derived interstitial 15q duplications experiences what phenotype?

Answer 22

Autism, NOT dysmorphic, often hypotonic during infancy, seizures common (Similar to IDIC 15)

Question 23

Phenyotype of Angelman Syndrome

Answer 23

Mildly dysmorphic facial features which evolve with age, hypotonia in infancy that progresses to spasticity in older patients, intellectual disability, seizures and autism.