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Weaver Syndrome
Thursday, 19 August 2004
Thursday, 19 August 2004
Weaver-Smith Syndrome


Weaver syndrome is a very rare genetic disorder. It is characterized as an overgrowth disorder because there is increased growth of the body in height and weight and the bones mature faster than they usually should. Weaver syndrome often causes certain facial features, a hoarse, low-pitched cry, increased muscle tone, and abnormally shaped hands and feet.


There have only been about 30 cases of Weaver syndrome reported. It occurs more often in males than females, and may occur in all ethnicities.

Signs and Symptoms

Children with Weaver syndrome may have few or many of the following features: Growth and Development: Weaver syndrome causes rapid physical growth of the body, which usually starts before birth. Individuals with this syndrome often have an increased height, weight, and head size as compared to other children of the same age. The bones grow and mature faster than usual (advanced bone age). The joints such as the elbows and knees cannot fully straighten. Children with Weaver syndrome can also have increased tone of the muscles. The skin may be loose and sagging. Weaver syndrome can cause varying degrees of developmental delay and mental retardation. Hands and Feet: The hands may be large with broad thumbs and prominent fingerpads. Often the fingers cannot straighten fully (camptodactyly), may be curved (clinodactyly), and the nails may be thin. The feet may be abnormally positioned, shaped, and high-arched with overlapping toes. Face: Weaver syndrome often causes characteristic facial features such as a large forehead, thin hair, large ears, eyes that are wider apart then usual (hypertelorism), small jaw, and a cleft lip. The chin is often distinctive and dimpled. Voice quality is often hoarse and low pitched and speech may be slurred and delayed. Other: Children with Weaver syndrome have also been known to have small abnormalities in the brain, seizures and/or behavior problems, and problems with breathing and swallowing. Abnormalities of the abdomen or genitalia (hernias) and undescended testes in males have also been noted.

Possible Causes

Most of the reported cases of Weaver syndrome have occurred sporadically, meaning that there is only one affected member in the family. All of us have genetic material that makes us who we are. The genetic material referred to as “chromosomes” are numbered. A gene for some cases of Weaver syndrome has been found on chromosome 5 called the NSD1 gene. Mistakes in this gene cause Weaver syndrome. All of us have two of almost every gene. Some cases of Weaver syndrome have been suggested to be an autosomal dominant genetic disorder. This means that the affected individual has one abnormal gene and one normal gene on chromosome 5. In autosomal dominant diseases, when a person has one abnormal gene, he or she is affected with the disease; in this case, Weaver syndrome.


Since only a few cases of Weaver syndrome have been reported, making a diagnosis of Weaver syndrome may be difficult. Doctors will need to differentiate Weaver syndrome from other growth and bone disorders. Imaging studies using X-rays, CT scans, and MRIs can help doctors see how the bones are growing and maturing, and also identify problems with the joints or other organs such as the brain. A sample of bone tissue may be taken and analyzed (bone biopsy).


Although there is no cure for Weaver syndrome, supportive treatment can help children with this syndrome. In addition to care from a pediatrician and a geneticist, an orthopedist and physical medicine specialist can help with problems of the bones, joints, and muscles. Reconstructive or plastic surgery may also be helpful to improve craniofacial (head and face), hand and foot abnormalities. Early educational intervention, physical, occupational, and speech therapies can help with developmental delay and speech problems.


Since there have only been a few cases of Weaver syndrome, the prognosis is not clear. However, some researchers suggest that the lifespan is relatively normal, unless there are significant problems (such as heart or brain defects).

Connect with other parents

In the spirit of community and support, Madisons Foundation offers the unique service of connecting parents of children with rare diseases. If you would like to be connected to other parents of children with this disease, please fill out this brief form.


The Weaver Syndrome Families Support Group c/o Patty Mayer 4357 153rd Avenue SE Belluvue, WA 98006 Phone #: (425) 747-5382, (206) 747-5382, (416) 948-5401 e-mail: This support group can be contacted for information and resources on Weaver syndrome, as well as to network with other families affected with Weaver syndrome. They currently have families from the US, Great Britain, and Canada. (No weblinks were found for this group.)

MAGIC Foundation for Children's Growth
Phone: (800)-362-4423  This foundation also helps connect families affected with the same syndrome.

GAPS Index
This website is a resource for genetic information about Weaver syndrome and parent services.

This website has general information on features of Weaver syndrome.

Google Search for Weaver Syndrome

References and Sources