Weaver Syndrome: Symptoms, Causes, and Clinical Management

Oct 11

6 min read

Updated: 3 days ago

Medically reviewed by Dr. Baraa Alnahhal, MD · Last reviewed: October 2026

TL;DR: Weaver syndrome, also known as Weaver-Smith syndrome, is an exceptionally rare genetic disorder characterized by accelerated bone overgrowth, distinct facial features, and varying degrees of intellectual disability. Caused by mutations in the EZH2 gene, the condition often manifests prenatally with fetal macrosomia and continues with rapid growth that can exceed standard pediatric charts. While there is no cure, a multidisciplinary approach involving orthopedic care, physical therapy, and awareness of neuroblastoma warning signs allows many individuals to live healthy lives into adulthood.

Quick Answer: What is Weaver syndrome?

Weaver syndrome is a rare genetic condition that makes bones grow too quickly, causing tall stature and advanced bone age, along with features such as wide-set eyes and a large head. It is caused by an EZH2 gene mutation and diagnosed through genetic testing. [1] Management is supportive, with awareness of childhood cancers, and many children live through adulthood. [1]

What the research says

Weaver syndrome is caused by changes in the EZH2 gene. Trio-based whole-exome sequencing of two affected families found two different de novo EZH2 mutations, and Sanger sequencing of a third classically affected person found a third de novo mutation in the same gene (According to PubMed, Gibson et al., Am J Hum Genet, 2012) [2].
Tall stature is the most consistent feature; faces can be subtle. Among 48 people with EZH2 mutations, tall stature was reported in more than 90% and intellectual disability in about 80% (highly variable and frequently mild), while facial features could be subtle, especially in older individuals, and the syndrome overlaps with Sotos syndrome (According to PubMed, Tatton-Brown et al., Am J Med Genet A, 2013) [3].
Neuroblastoma has been reported in Weaver syndrome. A case report described a third patient with Weaver syndrome and neuroblastoma; the authors note that overgrowth syndromes carry an increased risk of neoplasia and that evaluation for neuroblastoma should be considered in a child with Weaver-like features (According to PubMed, Coulter et al., J Pediatr Hematol Oncol, 2008) [4].

Genetic Origins and Pathophysiology

Weaver syndrome is a genetic disorder primarily driven by mutations in the EZH2 gene. [1] [2] This gene affects how other genes throughout the body are regulated; when it mutates, it triggers a chain reaction that results in bone overgrowth [1] and developmental changes. While about half of all people with Weaver syndrome inherited the mutation from a parent, the condition can also occur in families with no prior history of the disorder. [1]

The hallmark of Weaver syndrome is its effect on the skeletal system. Affected individuals often have "advanced bone age," a clinical term meaning their bones mature faster than is typical for their age. [1] This rapid maturation leads to tall stature, and the condition can also affect joints and the spine. [1] Because the condition is so rare—with only about 50 people identified worldwide [1]—clinical understanding continues to evolve through specialized genetic research.

Feature	Clinical Observation	Impact
Gene Mutation	EZH2 gene	Triggers bone overgrowth and affects other genes.
Inheritance	Autosomal dominant	About a 50% chance of passing the mutation to a child with each pregnancy. [1]
Bone Age	Advanced maturation	Results in rapid growth and tall stature.
Prevalence	About 50 people worldwide	Extremely rare, requiring specialized care.

Recognizing Symptoms and Physical Markers

Symptoms of Weaver syndrome can sometimes be detected even before birth. Prenatal ultrasounds may show that a fetus has unusually long bones or is larger than average (macrosomia). [1] At birth, infants may have a longer body length or higher birth weight and often have a low-pitched, hoarse, or scratchy cry. [1] As the child grows, their height may be so fast that it falls off the growth charts. [1]

Beyond rapid growth, Weaver syndrome is associated with several distinct facial and physical characteristics. These markers help clinicians distinguish it from similar conditions, such as Sotos syndrome.

Facial Features: A broad forehead, wide-set eyes (orbital hypertelorism), down-slanting eyelids, extra skin over the inner corner of the eyes (epicanthal folds), a large head (macrocephaly), and a small lower jaw (micrognathia) [1] are common.
Skeletal and Joint Issues: Children may have fingers that cannot straighten (camptodactyly), wide thumbs, clubfoot, elbows or knees that will not straighten, or a curvature of the spine (scoliosis). [1]
Developmental Milestones: Many children experience delays in meeting physical and cognitive milestones, with intellectual disabilities ranging from mild to severe. [1]

Illustration of the clinical markers of Weaver syndrome, including tall stature, macrocephaly, broad forehead, wide-set eyes, camptodactyly, and wide thumbs – rinnit.com

Diagnostic Procedures and Cancer Surveillance

If a healthcare provider suspects Weaver syndrome based on a child's growth pattern and physical appearance, genetic testing is used to look for a mutation in the EZH2 gene. [1] A small blood sample is sent to a laboratory. In some cases, doctors order a genetic testing panel to look for several mutations at once, which helps rule out other overgrowth conditions. [1]

An important part of care is awareness of neuroblastoma, a type of cancer that usually affects children under the age of five. [1] Although many children with Weaver syndrome never develop it, the risk may be higher than in the general population. [1] Parents are advised to watch for warning signs such as a lump in the neck or torso, a swollen belly, or fatigue with fever or cough, and to contact the child's provider if they notice them. [1]

Infographic of Weaver syndrome symptoms and diagnosis, showing prenatal signs, facial features, and the diagnostic pathway from physical exam to EZH2 genetic testing – rinnit.com

Clinical Management and Long-Term Outlook

There is currently no cure for Weaver syndrome [1], so medical care focuses on managing symptoms and improving quality of life. A care plan is usually multidisciplinary, involving specialists in genetics, orthopedics, cardiology, and behavioral health. Physical therapy is often a cornerstone of treatment, helping children develop muscle strength and coordination. [1]

For those with congenital heart conditions or problems with the joints, hands, or feet, surgery or other procedures may be needed. [1] Educational support, including tutoring and counseling, can help children manage intellectual disabilities and thrive in school. [1] Despite the challenges, people with Weaver syndrome can live healthy lives, and many children live through adulthood with regular medical care. [1]

Overview of the Weaver syndrome management pathway, including physical therapy, orthopedic care, educational support, cancer surveillance, and coordinated long-term follow-up – rinnit.com

Frequently Asked Questions

What is the most common sign of Weaver syndrome?

The most frequent characteristic is tall stature, often accompanied by bones that mature faster than normal (advanced bone age).

Is Weaver syndrome always inherited?

No. While it can be passed from a parent, it also occurs spontaneously in people with no family history of the condition.

How rare is Weaver syndrome?

Weaver syndrome is extremely rare; medical experts have only identified the condition in about 50 people worldwide.

Can Weaver syndrome be detected during pregnancy?

Signs may appear before birth. A prenatal ultrasound may show that the baby is larger than average or has unusually long bones.

What gene is responsible for Weaver syndrome?

The condition is caused by a mutation in the EZH2 gene, which affects how other genes throughout the body are regulated.

Does Weaver syndrome cause cancer?

Weaver syndrome may raise a child's risk of neuroblastoma, a childhood cancer, but many children with the syndrome never develop it.

What are the facial features of Weaver syndrome?

Common features include a broad forehead, wide-set eyes, large or low-set ears, down-slanting eyelids, and a small lower jaw.

How is the condition treated?

There is no cure, but symptoms are managed through physical therapy, orthopedic care, cardiac care when needed, and educational and behavioral support.

Do people with Weaver syndrome have intellectual disabilities?

Many do, though the severity ranges from mild to severe and varies significantly between individuals.

What is the life expectancy for someone with Weaver syndrome?

With regular medical care and management of associated risks like heart conditions, many people with Weaver syndrome live through adulthood.

References

Cleveland Clinic. Weaver Syndrome. Cleveland Clinic. Last updated 08/30/2022. https://my.clevelandclinic.org/health/diseases/24070-weaver-syndrome
Gibson WT, Hood RL, Zhan SH, et al. Mutations in EZH2 cause Weaver syndrome. Am J Hum Genet. 2012;90(1):110-118. PMID 22177091. https://doi.org/10.1016/j.ajhg.2011.11.018
Tatton-Brown K, Murray A, Hanks S, et al. Weaver syndrome and EZH2 mutations: clarifying the clinical phenotype. Am J Med Genet A. 2013;161A(12):2972-2980. PMID 24214728. https://doi.org/10.1002/ajmg.a.36229
Coulter D, Powell CM, Gold S. Weaver syndrome and neuroblastoma. J Pediatr Hematol Oncol. 2008;30(10):758-760. PMID 19011474. https://doi.org/10.1097/MPH.0b013e3181758974

Medical disclaimer

This article is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions about a medical condition.