Researchers have isolated a gene that causes Weaver syndrome.
Mutations in the EZH2 gene has been found to bring about the large birth size, tall stature, developmental delay and intellectual disability associated with the syndrome.
The discovery means that families who are seeking diagnostics for their child can be tested for specific gene mutation.
Dr William Gibson, the study's lead investigator, stated: "For the families among whom we identified the gene, this discovery definitely brings the diagnostic odyssey to a close - it's DNA confirmation that their children have Weaver syndrome."
However, there may be other Weaver syndrome genes which need to be identified, according to Dr Gibson.
EZH2 is also thought to play a key role in cancer development, by acting as a suppressor for cancer cell growth when dormant, but promoting oncogenesis when phosphorylated.
Researchers found the two forms of EZH2 after they identified the trigger - Akt - that leads to its phosphorylation.
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