Proteus syndrome is a rare genetic disorder[1] that can cause tissue overgrowth involving all three embryonic lineages.

[2] The clinical symptoms and radiographic findings of Proteus syndrome are highly variable, as are its orthopedic manifestations.

[8] Proteus syndrome causes an overgrowth of skin, bones, muscles, fatty tissues, and blood and lymphatic vessels.

[3] The severity and locations of these asymmetrical growths vary greatly but typically the skull, one or more limbs, and soles of the feet will be affected.

There is a risk of premature death in affected individuals due to deep vein thrombosis and pulmonary embolism caused by the vessel malformations that are associated with this disorder.

[citation needed] The disorder does not uniformly cause learning impairments: the distribution of intelligence deficits among those with Proteus syndrome appears higher than that of the general population.

In 26 of 29 patients who met strict clinical criteria for the disorder, Lindhurst et al. identified an activating mutation in AKT1 kinase in a mosaic state.

[11] A team of doctors in Australia has trial-tested the drug rapamycin in the treatment of a patient said to have Proteus syndrome and have found it to be an effective remedy.

[24] This trial is based on in vitro data showing inhibition of AKT1 in cell lines from patients with Proteus syndrome.