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ARHGAP31 gene

Rho GTPase activating protein 31

Normal Function

The ARHGAP31 gene provides instructions for making a protein classified as a Rho GTPase activating protein (GAP). GAPs turn off (inactivate) proteins called GTPases, which play an important role in chemical signaling within cells. Often referred to as molecular switches, GTPases can be turned on and off. They are turned on (active) when they are attached (bound) to a molecule called GTP and are turned off when they are bound to another molecule called GDP. The ARHGAP31 protein inactivates GTPases known as Cdc42 and Rac1 by stimulating a reaction that turns the attached GTP into GDP. When active, Cdc42 and Rac1 transmit signals that are critical for various aspects of embryonic development. The ARHGAP31 protein appears to regulate these GTPases specifically during development of the limbs, skull, and heart.

Health Conditions Related to Genetic Changes

Adams-Oliver syndrome

At least three mutations in the ARHGAP31 gene are known to cause Adams-Oliver syndrome, a condition characterized by areas of missing skin (aplasia cutis congenita), usually on the scalp, and malformations of the hands and feet. These mutations lead to production of an abnormally short ARHGAP31 protein that is more active than normal. The increased GAP activity leads to a reduction in Cdc42 and Rac1 signaling, which impairs proper development of the skin on the top of the head and the bones in the hands and feet.

More About This Health Condition

Other Names for This Gene

  • AOS1
  • Cdc42 GTPase-activating protein
  • rho GTPase-activating protein 31

Additional Information & Resources

Tests Listed in the Genetic Testing Registry

Scientific Articles on PubMed

Catalog of Genes and Diseases from OMIM

Gene and Variant Databases


  • Isrie M, Wuyts W, Van Esch H, Devriendt K. Isolated terminal limb reduction defects: extending the clinical spectrum of Adams-Oliver syndrome and ARHGAP31 mutations. Am J Med Genet A. 2014 Jun;164A(6):1576-9. doi: 10.1002/ajmg.a.36486. Epub 2014 Mar 25. Citation on PubMed
  • Raftopoulou M, Hall A. Cell migration: Rho GTPases lead the way. Dev Biol. 2004 Jan 1;265(1):23-32. doi: 10.1016/j.ydbio.2003.06.003. Citation on PubMed
  • Southgate L, Machado RD, Snape KM, Primeau M, Dafou D, Ruddy DM, Branney PA, Fisher M, Lee GJ, Simpson MA, He Y, Bradshaw TY, Blaumeiser B, Winship WS, Reardon W, Maher ER, FitzPatrick DR, Wuyts W, Zenker M, Lamarche-Vane N, Trembath RC. Gain-of-function mutations of ARHGAP31, a Cdc42/Rac1 GTPase regulator, cause syndromic cutis aplasia and limb anomalies. Am J Hum Genet. 2011 May 13;88(5):574-85. doi: 10.1016/j.ajhg.2011.04.013. Citation on PubMed or Free article on PubMed Central
  • Tcherkezian J, Lamarche-Vane N. Current knowledge of the large RhoGAP family of proteins. Biol Cell. 2007 Feb;99(2):67-86. doi: 10.1042/BC20060086. Citation on PubMed

The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.