The Path to Diagnosis: Scoring and Genetic Testing
At a Glance
Beckwith-Wiedemann Syndrome (BWS) is diagnosed using a clinical scoring system based on physical features, followed by genetic testing. Because BWS can involve mosaicism, a normal blood test does not rule out the condition, and testing other tissues like skin may be necessary for confirmation.
Diagnosing Beckwith-Wiedemann Syndrome (BWS) has evolved. Because it is a “spectrum” disorder, doctors no longer rely on a simple “yes or no” list [1]. Instead, they use a sophisticated scoring system and advanced genetic testing to create a personalized care plan for your child [2][3].
The 2018 International Consensus Scoring System
To help doctors identify where a child sits on the spectrum, the 2018 International Consensus Statement created a clinical scoring system [2][4]. Symptoms are divided into two categories:
- Cardinal Features (2 points each): These are the major signs, such as macroglossia (large tongue), omphalocele (abdominal wall defect), or lateralized overgrowth (one side of the body larger than the other) [5][6].
- Suggestive Features (1 point each): These are minor or more common signs, such as neonatal hypoglycemia (low blood sugar at birth), ear creases/pits, or enlarged internal organs (like the liver or kidneys) [5][7].
What the Score Means
- Score of 4 or more: This is considered a clinical diagnosis of classic BWS [8].
- Score of 2 or more: This is the “threshold” where doctors typically recommend molecular (genetic) testing to confirm the diagnosis [2][9].
The Diagnostic Pathway: From Blood to Tissue
The first step in confirmation is usually a blood test to look for genetic changes on chromosome 11p15.5 [10]. However, this is where it can get tricky for parents.
Understanding Mosaicism
Many children with BWS have epigenetic mosaicism [11][12]. “Mosaicism” means that the genetic change is not present in every cell in the body [11]. It is like a mosaic tile floor where some tiles are one color (the BWS change) and others are a different color (normal cells) [12].
Because of this, a blood test may come back “normal” (negative) even if your child has BWS [11][12]. This happens because the blood cells might be the “normal” tiles, while the “BWS” tiles are located in other parts of the body, like the tongue, skin, or liver [13][11].
Why Further Testing Matters
If your child has a high clinical score but a negative blood test, your doctor may recommend testing a second tissue sample [13][14]. This might include:
- A small skin sample (biopsy) [13].
- A sample of tissue from a tongue reduction or umbilical cord repair surgery [13][11].
Confirming the diagnosis through these other tissues is vital because it helps identify the specific molecular subtype [15]. This “subtype” is the blueprint that tells your medical team exactly which tumors to look for and how often to screen for them [10][15]. Knowing the molecular cause provides the most accurate roadmap for your child’s long-term health [15][3].
Common questions in this guide
What clinical score is needed to diagnose Beckwith-Wiedemann Syndrome?
Why might a BWS blood test come back normal even if my child has symptoms?
What are the cardinal features of Beckwith-Wiedemann Syndrome?
If a blood test is negative for BWS, what is the next step?
Questions to Ask Your Doctor
Curated prompts to bring to your next appointment.
- 1.What is my child's total score on the 2018 International Consensus clinical scoring system?
- 2.If my child's blood test was negative, does that completely rule out BWS, or should we consider testing another tissue?
- 3.Is my child's current screening schedule based on their clinical score or a confirmed molecular subtype?
- 4.Because of the possibility of mosaicism, which tissue (skin, tongue, etc.) would be most reliable to test next if the blood test was normal?
- 5.How does a 'classic' BWS diagnosis (score of 4+) change our immediate next steps compared to a lower score?
Questions For You
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References
References (15)
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PMID: 29377879 - 11
Somatic Mosaicism for Paternal Uniparental Disomy of 11p15.5 Region in Adrenal and Liver Tissues in a Newborn with Atypical Beckwith-Wiedemann Syndrome.
Urzua A, Burattini S, Pinochet C, et al.
Journal of pediatric genetics 2019; (8(4)):226-230 doi:10.1055/s-0039-1692197.
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Improved molecular detection of mosaicism in Beckwith-Wiedemann Syndrome.
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Characteristics Associated with Tumor Development in Individuals Diagnosed with Beckwith-Wiedemann Spectrum: Novel Tumor-(epi)Genotype-Phenotype Associations in the BWSp Population.
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This page explains Beckwith-Wiedemann Syndrome diagnostic scoring and genetic testing for educational purposes. Always consult a pediatric geneticist or your child's medical team for a formal diagnosis and tailored testing plan.
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