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Reviewed January 2013

What is the official name of the GNAI3 gene?

The official name of this gene is “guanine nucleotide binding protein (G protein), alpha inhibiting activity polypeptide 3.”

GNAI3 is the gene's official symbol. The GNAI3 gene is also known by other names, listed below.

Read more about gene names and symbols on the About page.

What is the normal function of the GNAI3 gene?

The GNAI3 gene provides instructions for making one component, the inhibitory alpha subunit, of a protein complex called a guanine nucleotide-binding protein (G protein). G proteins are composed of three protein subunits: alpha, beta, and gamma. Each of these subunits is produced from a different gene.

Through a process called signal transduction, G proteins trigger a complex network of signaling pathways within cells. These pathways help transmit information from outside the cell to inside the cell. Specifically, G proteins made with the GNAI3 inhibitory alpha subunit reduce (inhibit) the activity of an enzyme called adenylyl cyclase, which is an important chemical messenger within cells. G protein signaling ultimately influences many cell activities, instructing the cell to grow, divide, or take on specialized functions.

Studies suggest that G protein signaling involving the GNAI3 inhibitory alpha subunit contributes to the development of the first and second pharyngeal arches. These embryonic structures ultimately develop into the jawbones, facial muscles, middle ear bones, ear canals, outer ears, and related tissues.

How are changes in the GNAI3 gene related to health conditions?

auriculo-condylar syndrome - caused by mutations in the GNAI3 gene

At least two mutations in the GNAI3 gene have been found to cause auriculo-condylar syndrome, a disorder that primarily affects the development of the ears and lower jaw (mandible). The identified mutations change single protein building blocks (amino acids) in the inhibitory alpha subunit. These mutations likely alter the structure of the inhibitory alpha subunit and impair G protein signaling. Abnormal signaling alters the formation of the lower jaw: instead of developing normally, the lower jaw becomes shaped more like the smaller upper jaw (maxilla). The abnormal shape leads to an unusually small chin (micrognathia) and problems with jaw function. Researchers are working to determine how mutations in this gene lead to the other developmental abnormalities associated with auriculo-condylar syndrome.

Where is the GNAI3 gene located?

Cytogenetic Location: 1p13

Molecular Location on chromosome 1: base pairs 109,548,564 to 109,595,843

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBIThis link leads to a site outside Genetics Home Reference.)

The GNAI3 gene is located on the short (p) arm of chromosome 1 at position 13.

The GNAI3 gene is located on the short (p) arm of chromosome 1 at position 13.

More precisely, the GNAI3 gene is located from base pair 109,548,564 to base pair 109,595,843 on chromosome 1.

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

Where can I find additional information about GNAI3?

You and your healthcare professional may find the following resources about GNAI3 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 GNAI3 gene or gene products?

  • 87U6
  • ARCND1
  • g(i) alpha-3
  • guanine nucleotide-binding protein G(k) subunit alpha

Where can I find general information about genes?

The Handbook provides basic information about genetics in clear language.

These links provide additional genetics resources that may be useful.

What glossary definitions help with understanding GNAI3?

acids ; cell ; embryonic ; enzyme ; gene ; guanine ; lower jaw ; mandible ; maxilla ; micrognathia ; neural crest ; nucleotide ; protein ; receptor ; signal transduction ; subunit ; syndrome ; transduction ; upper jaw

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

See also Understanding Medical Terminology.

References (6 links)


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: January 2013
Published: February 1, 2016