Weaver syndrome is a condition that involves tall stature with or without a large head size (macrocephaly), a variable degree of intellectual disability (usually mild), and characteristic facial features. These features can include a broad forehead; widely spaced eyes (hypertelorism); large, low-set ears; a dimpled chin, and a small lower jaw (micrognathia).

Weaver syndrome is usually caused by mutations in the EZH2 gene. The EZH2 gene provides instructions for making a type of enzyme called a histone methyltransferase. Histone methyltransferases modify proteins called histones, which are structural proteins that attach (bind) to DNA and give chromosomes their shape. By adding a molecule called a methyl group to histones (methylation), histone methyltransferases can turn off the activity of certain genes, which is an essential process in normal development. It is unclear how mutations in the EZH2 gene result in the abnormalities characteristic of Weaver syndrome.

The prevalence of Weaver syndrome is unknown. About 50 affected individuals have been described in the medical literature.

This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. Most cases result from new mutations in the gene and occur in people with no history of the disorder in their family. In a small number of cases, an affected person inherits the mutation from one affected parent.

Published Date: March 01, 2016
Published By: National Institutes of Health