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Proteus syndrome


Friday 25 July 2003

Definition: Proteus syndrome is a rare, sporadic disorder that causes postnatal overgrowth of multiple tissues in a mosaic pattern. A mosaic activating mutation in AKT1 is associated with the Proteus syndrome. (21793738)

Characteristic manifestations include: overgrowth and hypertrophy of limbs and digits, connective tissue nevus, epidermal nevus and hyperostoses. Various benign and malignant tumors and hamartomas may complicate the clinical course of patients with the syndrome.

Proteus syndrome is a highly variable, severe disorder of asymmetric and disproportionate overgrowth of body parts, connective tissue nevi, epidermal nevi, dysregulated adipose tissue, and vascular malformations.

Many features of Proteus syndrome overlap with other overgrowth syndromes. The disorder might be confused with the Klippel-Trenaunay-Weber syndrome (MIM.149000) and with Ollier disease and Maffucci syndrome (MIM.166000).

PTEN-associated Proteus-like syndrome

Some authors (Zhou et al., 2000, 2001; Smith et al., 2002) have reported a ’Proteus-like’ syndrome associated with germline and tissue-specific somatic mutations in the PTEN gene (MIM.601728), which is mutated in Cowden syndrome (MIM.158350) and Bannayan-Riley-Ruvalcaba syndrome (BRRS; MIM.153480).


- Growth

  • asymmetric overgrowth
  • increased stature
  • macrocephaly

- Skin & subcutaneous tissue

  • thickening
  • nevi
  • lipomata
  • lymphangiomata
  • hemangiomata

- Skeletal : hemihypertrophy, bony prominences over skull, angulation defects of knees, scoliosis

- Hands & feet : macrodactyly, soft tissue hyper-trophy, which may appear as gyriform

Tumoral predisposition

- hemangiomas
- lymphangiomas
- lipomas
- tumors of the genital tract


- germline mutation in the tumor suppressor gene PTEN (MIM.601728)
- A mosaic activating mutation in AKT1 is associated with the Proteus syndrome. (21793738)

Differential diagnosis

- Klippel-Trenaunay-Weber syndrome (MIM.149000)
- Ollier disease and Maffucci syndrome (MIM.166000)


- A mosaic activating mutation in AKT1 associated with the Proteus syndrome. Lindhurst MJ, Sapp JC, Teer JK, Johnston JJ, Finn EM, Peters K, Turner J, Cannons JL, Bick D, Blakemore L, Blumhorst C, Brockmann K, Calder P, Cherman N, Deardorff MA, Everman DB, Golas G, Greenstein RM, Kato BM, Keppler-Noreuil KM, Kuznetsov SA, Miyamoto RT, Newman K, Ng D, O’Brien K, Rothenberg S, Schwartzentruber DJ, Singhal V, Tirabosco R, Upton J, Wientroub S, Zackai EH, Hoag K, Whitewood-Neal T, Robey PG, Schwartzberg PL, Darling TN, Tosi LL, Mullikin JC, Biesecker LG. N Engl J Med. 2011 Aug 18;365(7):611-9. PMID: 21793738