What Are the Adult Medical Complications of BWS?

As children with Beckwith-Wiedemann syndrome (BWS) grow into adults, their medical needs change significantly. The most reassuring news is that the intense medical surveillance and heightened risk for childhood tumors drop off by age 7 or 8. Most adults with BWS have a normal life expectancy and enjoy a typical quality of life ^[1]. However, based on the 2018 International Consensus Statement on BWS, there are a few specific areas—such as kidney health, lasting physical differences, and genetic counseling—that require attention during adulthood ^[1][2].

The End of Childhood Cancer Screenings

The most stressful part of a BWS diagnosis for parents is the increased risk of childhood embryonal tumors (cancers that develop from fetal cells), such as Wilms tumor and hepatoblastoma ^[3]. Because these are specifically childhood cancers, the risk decreases dramatically as a child grows. Routine pediatric cancer surveillance protocols—like abdominal ultrasounds and blood tests—are well-established but generally end around age 7 or 8, depending on the specific molecular subtype ^[1][3].

While a few rare cases of adult-onset tumors (such as insulinomas, a rare tumor of the pancreas, or breast tumors) have been reported in adults with BWS ^[4][5], the absolute risk remains unknown and is considered rare ^[5]. Currently, there are no intense, BWS-specific cancer surveillance protocols required for adults. Adults should simply follow standard cancer screening guidelines recommended for the general public, while ensuring their primary care doctor is aware of their medical history.

Physical Features and Growth in Adulthood

BWS is an overgrowth syndrome, and many families wonder if growth will continue abnormally into adulthood. The rapid overgrowth seen in childhood generally normalizes over time, and body asymmetry caused by hemihyperplasia (uneven growth on one side of the body) often becomes less apparent as the child reaches adulthood ^[6][7]. However, some adults may experience lasting orthopedic issues, such as uneven leg lengths, which may require monitoring for back or joint pain.

Additionally, infants who had macroglossia (an enlarged tongue) may have had tongue reduction surgeries to help with feeding, breathing, and speech ^[8]. While these surgeries are highly effective for function, some adults may still develop a prominent lower jaw or an underbite (Class III malocclusion) that requires orthodontic or jaw (maxillofacial) care later in life ^[9].

Kidney Health in Adulthood

One of the most important areas to monitor in adult BWS patients is kidney (renal) health. Nonmalignant kidney abnormalities can persist or become evident later in life ^[10].

Specifically, adults with BWS may be at risk for medullary sponge kidney (MSK) ^[11]. MSK is a condition where the tiny tubes inside the kidney become widened or dilated, which can lead to a buildup of calcium ^[12]. Individuals with MSK are more prone to developing recurrent kidney stones (often made of calcium phosphate) and may experience pain or urinary infections ^[13][12]. MSK is generally diagnosed in adulthood ^[12]. If kidney issues arise, management focuses strictly on preventing new kidney stones from forming or growing by using specific medications (like potassium citrate) or diet modifications ^[14]. Once calcium stones form, they cannot be dissolved by medication or diet.

Long-Term Effects of Infant Hypoglycemia

Many infants with BWS experience hyperinsulinemic hypoglycemia (dangerously low blood sugar caused by too much insulin) ^[15]. In most cases, this is closely managed in infancy and resolves.

If an infant experienced severe and prolonged hypoglycemia that was difficult to treat, it is a recognized risk factor for subtle long-term neurodevelopmental challenges, such as differences in executive function (planning and focusing) or visual-motor skills ^[16][17]. However, if the low blood sugar was promptly and successfully managed above safe thresholds, it is strongly associated with the prevention of these adverse neurological outcomes ^[18]. Early hypoglycemia management is a successful intervention that protects long-term brain health.

Family Planning and Genetics

As adults with BWS think about having children of their own, they often wonder if they will pass the condition on. The recurrence risk varies wildly depending on the patient’s molecular subtype (the specific genetic or epigenetic cause of their BWS) ^[1]. While many cases of BWS are isolated and have less than a 1% chance of being passed on, other subtypes (such as a CDKN1C mutation) can have up to a 50% chance of being inherited ^[19]. It is highly recommended that adults with BWS seek genetic counseling before starting a family so they understand their specific risks.

Transitioning to Adult Care

As teens with BWS prepare to transition from pediatric to adult care, the 2018 International Consensus recommends addressing multi-systemic health needs by creating a comprehensive medical summary ^[1][20]. Having this information empowers adult patients to advocate for their health and ensures their adult care team understands which rare conditions, like MSK, to keep on their radar ^[2].

Adult Transition Checklist:
When gathering pediatric records for the transition to adulthood, ensure you have documented the following:

• The Specific Molecular Subtype: The exact genetic test results confirming the BWS diagnosis (crucial for future family planning and determining when cancer screenings should end).
• Hypoglycemia History: A summary of whether severe low blood sugar occurred as a newborn and how it was managed.
• Imaging History: A baseline kidney ultrasound report and any records of childhood tumors.
• Surgical History: Records of any early interventions like tongue reductions or orthopedic surgeries.