Weaver syndrome is a genetic disorder. The most familiar characteristic of Weaver syndrome is faster than average growth. Weaver syndrome is currently considered a rare disorder. Because of the heritable nature of this condition, expecting parents and those planning to become pregnant may find information about the condition especially relevant. Weaver syndrome is sometimes called Weaver-Smith syndrome, or WSS for short.
Definition & Facts
Weaver syndrome is considered extremely rare, and only an estimated 50 cases have been reported to date through medical studies. Because there are so few individuals to study, progress towards developing a better understanding of the condition and earlier detection methods is slow.
A related disorder is called Marshall-Smith syndrome, but in this disorder, individuals are usually under their ideal weight and have some respiratory issues and different physical appearance issues than those individuals who have true Weaver syndrome. Another related disorder is Soto syndrome, which presents with many symptoms similar to Weaver. In Soto syndrome, excessive growth is the chief hallmark, along with certain neurological issues such as increased aggression and clumsiness.
Because each of these syndromes is currently quite rare and share many very similar symptoms, it can sometimes take some time to identify the exact diagnosis as Weaver syndrome.
Symptoms & Complaints
- Abnormalities of gyri of the brain
- Joint abnormalities.
- Unusually heightened muscle tone (hypertonia) or poor muscle tone (hypotonia).
- Some level of intellectual disability or cognitive impairment.
- An abnormally curved spine (scoliosis).
- Skin that appears loose and sags.
- An umbilical hernia.
- Increased risk to develop neuroblastoma, a cancer that can affect the internal organs (in particular the kidneys).
- Inverted nipples.
- Thin hair.
- Inability to extend elbows or knees very far.
- Low, hoarse cry (in infants).
Weaver syndrome is known to be heritable - that is, it can be passed from parent to child. In 2011, a research study published in Science Daily was able to pinpoint a gene that causes Weaver syndrome. Called EZH2, this gene can cause Weaver syndrome when it mutates.
Complicating factors for determining the cause of Weaver syndrome still remain, however. This is because, in some cases, testing can locate no genetic link and the cause remains completely unknown.
Diagnosis & Tests
Thus far, it appears that males are three times more likely to develop Weaver syndrome than females. Typically, Weaver syndrome presents before the infant is even born. The best way to diagnose Weaver syndrome pre-birth is for the prospective parents to undergo genetic testing (prenatal diagnosis).
Genetic testing will look for the presence of overgrowth due to the EZH2 gene. If genetic testing has not been performed, Weaver syndrome may also be diagnosed by looking for a majority of known symptoms as outlined here via physical examination. The main diagnostic challenge is that Weaver syndrome can occur across a wide spectrum of symptoms.
In some individuals who have very mild cases, they may only display symptoms regarding height to indicate the presence of Weaver syndrome. Other individuals (approximately 80 percent) may have mild cognitive dysfunction. Still others may have a "classic" case of Weaver syndrome with the full array of telltale symptoms. Tests that can be helpful in diagnosing Weaver syndrome include these:
- X-ray of the cervical vertebrae
- Magnetic resonance imaging (MRI) to diagnose brain abnormalities.
- Ultrasound of the retroperitoneal space every 3 months or as needed to detect growth of neuroblastoma tumors.
Treatment & Therapy
The treatment for Weaver syndrome at this time is based on the goal of treating symptoms as they arise rather than curing the underlying condition, for which there is no cure. For example, if the individual has a club foot due to malformation of the joint, it may be possible to correct this through surgical treatment.
In this way, treatment and therapy typically involves a multi-disciplinary team, each working in their area of specialty to correct for various symptoms as best as possible. Typical team members include the following medical specialists:
For young individuals diagnosed with Weaver syndrome in particular, careful monitoring for the growth of neuroblastoma cancer tumors is recommended, especially before they reach their third birthday.
Often, parents and loved ones of an individual with more severe Weaver syndrome symptoms also need significant support to help manage the condition. In some countries, foundations are now offering support to individuals and families as well as funding additional research to better understand the condition and treatment options.
Individuals with very mild Weaver syndrome may not need much if any treatment and are often able to lead a relatively normal life. Sometimes the symptoms are mild enough that diagnosis only comes when a younger family member presents with more severe symptoms of Weaver syndrome and adult family members are then tested as well.
Prevention & Prophylaxis
However, because the condition usually presents before the child is even born, the only way to address Weaver syndrome at this time is through managing symptoms as is possible. As more research is done and public awareness of Weaver syndrome grows, additional prevention options may be discovered.