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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed November 2008

What is the official name of the FGD1 gene?

The official name of this gene is “FYVE, RhoGEF and PH domain containing 1.”

FGD1 is the gene's official symbol. The FGD1 gene is also known by other names, listed below.

What is the normal function of the FGD1 gene?

The FGD1 gene provides instructions for making a protein known as a guanine nucleotide exchange factor (GEF). GEFs turn on (activate) proteins called GTPases, which play an important role in chemical signaling within cells. GTPases are turned off (inactivated) when they are attached (bound) to a molecule called GDP and are activated when they are bound to another molecule called GTP. The FGD1 protein activates the GTPase known as Cdc42 by stimulating the exchange of GDP for GTP. Once Cdc42 is active, it transmits signals that are critical for various aspects of embryonic development, particularly formation of the skeleton.

Does the FGD1 gene share characteristics with other genes?

The FGD1 gene belongs to a family of genes called ARHGEF (Rho guanine nucleotide exchange factors). It also belongs to a family of genes called ZFYVE (zinc fingers, FYVE-type).

A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? ( in the Handbook.

How are changes in the FGD1 gene related to health conditions?

Aarskog-Scott syndrome - caused by mutations in the FGD1 gene

Approximately 20 mutations in the FGD1 gene have been found to cause Aarskog-Scott syndrome. These mutations lead to the production of an abnormally functioning protein, which disrupts Cdc42 signaling. Altering the transmission of Cdc42 signals results in the wide variety of developmental abnormalities seen in Aarskog-Scott syndrome.

Where is the FGD1 gene located?

Cytogenetic Location: Xp11.21

Molecular Location on the X chromosome: base pairs 54,445,454 to 54,496,166

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBI (

The FGD1 gene is located on the short (p) arm of the X chromosome at position 11.21.

The FGD1 gene is located on the short (p) arm of the X chromosome at position 11.21.

More precisely, the FGD1 gene is located from base pair 54,445,454 to base pair 54,496,166 on the X chromosome.

See How do geneticists indicate the location of a gene? ( in the Handbook.

Where can I find additional information about FGD1?

You and your healthcare professional may find the following resources about FGD1 helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the FGD1 gene or gene products?

  • AAS
  • faciogenital dysplasia protein
  • FGDY
  • ZFYVE3

See How are genetic conditions and genes named? ( in the Handbook.

What glossary definitions help with understanding FGD1?

domain ; dysplasia ; embryonic ; gene ; GTP ; guanine ; molecule ; nucleotide ; pH ; protein ; syndrome

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.


  • Estrada L, Caron E, Gorski JL. Fgd1, the Cdc42 guanine nucleotide exchange factor responsible for faciogenital dysplasia, is localized to the subcortical actin cytoskeleton and Golgi membrane. Hum Mol Genet. 2001 Mar 1;10(5):485-95. (
  • Gorski JL, Estrada L, Hu C, Liu Z. Skeletal-specific expression of Fgd1 during bone formation and skeletal defects in faciogenital dysplasia (FGDY; Aarskog syndrome). Dev Dyn. 2000 Aug;218(4):573-86. (
  • Hou P, Estrada L, Kinley AW, Parsons JT, Vojtek AB, Gorski JL. Fgd1, the Cdc42 GEF responsible for Faciogenital Dysplasia, directly interacts with cortactin and mAbp1 to modulate cell shape. Hum Mol Genet. 2003 Aug 15;12(16):1981-93. (
  • NCBI Gene (
  • Orrico A, Galli L, Cavaliere ML, Garavelli L, Fryns JP, Crushell E, Rinaldi MM, Medeira A, Sorrentino V. Phenotypic and molecular characterisation of the Aarskog-Scott syndrome: a survey of the clinical variability in light of FGD1 mutation analysis in 46 patients. Eur J Hum Genet. 2004 Jan;12(1):16-23. (


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? ( in the Handbook.

Reviewed: November 2008
Published: February 1, 2016