Updated: 12/24/2021

Prader-Willi Syndrome

0%
Topic
Review Topic
0
0
N/A
N/A
Questions
1
0
0
Topic
Images
https://upload.medbullets.com/topic/120569/images/prader-willi-syndrome_1680-painting-at-the-prado-by-juan-carreno-de-miranda1.jpg
https://upload.medbullets.com/topic/120569/images/prader-willi syndrome - wiki.jpg
  • Snapshot
    • A 33-year-old woman delivers a baby girl at full-term without complications. During a breastfeeding session, a lactation specialist notes that the neonate has poor muscle tone, poor suck, and a weak cry. Her basic laboratory results are normal. As hypotonia is classically associated with a genetic condition, a geneticist is consulted for further discussion.
  • Introduction
    • Overview
      • Prader-Willi syndrome is a disorder of imprinting associated with mutation or deletion of chromosome 15q11-13
  • Epidemiology
    • Incidence
      • 1 in 16,000-25,000
  • ETIOLOGY
    • Pathogenesis
      • the maternal allele on chromosome 15q11.2-13 is normally methylated or silenced
      • mutation or deletion of the paternal allele then results in complete absence or defective gene expression, leading to Prader-Willi syndrome
    • Genetics
      • inheritance pattern
        • sporadic
      • mutations
        • 25% due to maternal uniparental disomy (2 copies of maternal chromosome 15)
        • majority of cases are due to a mutation or deletion in paternal chromosome 15q11.2-13
          • genes identified include SNRPN, UBE3A, and necdin genes
    • Associated conditions
      • growth hormone deficiency
  • Presentation
    • Symptoms
      • intellectual disability
      • hyperphagia
      • behavioral problems
    • Physical exam
      • neonate and infant
        • hypotonia
        • poor suck
        • failure to thrive
        • weak cry
        • genital hypoplasia
        • cryptorchidism
      • toddlers
        • delayed developmental milestones
      • children
        • obesity
        • small hands and feet
        • short stature
        • strabismus
        • scoliosis
  • Imaging
    • Radiograph
      • indication
        • assess for scoliosis
      • findings
        • curvature of spine
  • Studies
    • Serum labs
      • fasting levels of insulin-like growth factor 1 and insulin-like growth factor binding protein-3
        • screen for underlying growth hormone deficiency
        • confirm with provacative growth hormone stimulation test
    • Genetic testing
      • chromosomal or microarray analysis
      • prenatal testing via chorionic villus sampling or amniocentesis
  • Differential
    • Angelman syndrome
      • key distinguishing factors
        • silenced maternal genomic material at chromosome 15q11.2-13
        • characterized by excessive laughter, hyperexcitability, and hand flapping
  • Treatment
    • Lifestyle
      • behavioral therapy
        • critical for conditioning child to normal eating habits and avoiding hyperphagia
      • diet and exercise
        • often requires coordination between home and school
      • calorie restriction
    • Medical
      • growth hormone
        • indications
          • growth failure
          • growth hormone deficiency
      • hormone-replacement therapy
        • indications
          • delayed puberty
    • Surgical
      • feeding tube
        • indication
          • growth failure in infancy
  • Complications
    • Hypopituitarism with deficiency in growth hormone
    • Scoliosis
    • Obstructive sleep apnea
    • Cor pulmonale
  • Prognosis
    • Patients are typically able to function well into adulthood

Please rate this review topic.

You have never rated this topic.

Thank you. You can rate this topic again in 12 months.

Flashcards (0)
Cards
1 of 0
Questions (1)
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
EXPERT COMMENTS (4)
Private Note