Beckwith-Wiedemann Syndrome

Background

  • Disorder characterized by overgrowth
  • Presents with variable severity
  • Caused by a wide range of genetic defects
    • Greater than 85% of cases are sporadic
    • Testing often does not reveal the specific defect, and genetic or epigenetic changes remain unknown in 1/5 or 1/3 of affected individuals
    • Most patients have disruptions, rearrangements, mutations, paternal uniparental disomy, or methylation abnormalities involving chromosome 11p15
    • Critical genes in the 11p15 region include insulin like growth factor (IGF2), cyclin-dependent kinase inhibitor 1C (CDKN1C), and imprinting centers 1 and 2 (IC1 and IC2)
      • IC1 and IC2 regulate expression of IGF2 and other pro-proliferation genes

Epidemiology

  • Prevalence of 1:13700 (may be an underestimation due to children with mild phenotypes who may go undiagnosed)

Clinical Features

  • Macrosomia (birth weights >90th percentile)
  • Macroglossia (present in 90% of children)

BWS_Mbuyi-Musanzayi2014a.jpg

Source: http://www.forgottendiseases.org/assets/Beckwith_Wiedemann_syndrome.html
  • Red birthmark on forehead or eyes (Nevus flammeus)
  • Midline abdominal defects (most commonly omphalocele or umbilical heria)

Omphalocele-300x225.jpg

Source: http://healthfoxx.com/beckwith-wiedemann-syndrome-pictures-prognosis-management/
  • Neonatal hypoglycemia (occurs in 1/2 of infants)
    • Almost always asymptomatic, normalize within the first three days of life
  • Hemihypertrophy/hemihyperplaisa (can be isolated to one limb or body part, associated with an increased risk of cancer)
  • Organomegaly
  • Ear abnormalities (creases or pits in the ear)

BWSimage10037.jpg

Source: http://atlasgeneticsoncology.org//Kprones/BeckwithWiedemannID10037.html
  • Increased neoplasm risk (~600 times more):
    • Wilms tumors or hepatoblastoma
    • Greater than 80% of children do not develop cancer
    • Risk is most elevated in childhood prior to age 10

Diagnosis

BWS is often suspected due to the presence of clinical features with or without hypoglycemia. Diagnosis is then confirmed with chromosomal studies for abnormalities in chromosome 11.

Pertinent tests include:

  • Blood glucose testing
  • Genetic testing
  • Abdominal MRI or CT followd by abdominal ultrasounds to screen for tumors every three months until age eight
  • Alpha-fetoprotein (AFP) to screen for tumors every six weeks until age four

Treatment:

Nonsurgical

  • Infants with BWS must have their blood glucose monitored at birth, and persistent hypoglycemia can be corrected with increased feedings or IV fluids.
    • Children with persistent hypoglycemia after the neonatal (<5%) require more intensive treatment regimens
  • Increased cancer screenings

Surgical

  • Correction of abdominal defect
  • Reduction of macroglossia if indicated by feeding difficulties or airway obstruction
  • Children with BWS typically live normal lives and have not been shown to have significant cognitive delays compared to siblings

Resources for Parents:

www.myBWSbaby.com

http://www.bws-support.org.uk/

References:

Baiocchi M, Yousuf FS, Hussain K. Hypopituitarism in a Patient With Beckwith-Wiedemann Syndrome Due to Hypomethylation of KvDMR1. Pediatrics. 2014 Apr 1;133(4):e1082.

Pappas JG. The clinical course of an overgrowth syndrome, from diagnosis in infancy through adulthood: the case of Beckwith-Wiedemann syndrome. Curr Probl Pediatr Adolesc Health Care. 2015 Apr;45(4):112–7.

Weksberg R, Shuman C, Beckwith JB. Beckwith-Wiedemann syndrome. Eur J Hum Genet. 2010 Jan;18(1):8–14.

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