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Genetics Home Reference: your guide to understanding genetic conditions
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IFT122

Reviewed November 2013

What is the official name of the IFT122 gene?

The official name of this gene is “intraflagellar transport 122.”

IFT122 is the gene's official symbol. The IFT122 gene is also known by other names, listed below.

What is the normal function of the IFT122 gene?

The IFT122 gene provides instructions for making a protein that is involved in the formation and maintenance of cilia, which are microscopic, finger-like projections that stick out from the surface of cells. Cilia participate in signaling pathways that transmit information within and between cells and are important for the development and function of many types of cells and tissues, including cells in the kidneys and liver and the light-sensitive tissue at the back of the eye (the retina). Cilia also play a role in the development of the bones, although the mechanism is not well understood.

The movement of substances within cilia and similar structures called flagella is known as intraflagellar transport. This process is essential for the assembly and maintenance of these cell structures. During intraflagellar transport, cells use molecules called IFT particles to carry materials to and from the tips of cilia. Each IFT particle is made up of two groups of IFT proteins: complex A and complex B. The protein produced from the IFT122 gene forms part of IFT complex A (IFT-A). During intraflagellar transport, this complex carries materials from the tip to the base of cilia.

The IFT-A complex is essential for proper regulation of the Sonic Hedgehog signaling pathway, which is important for the growth and maturation (differentiation) of cells and the normal shaping (patterning) of many parts of the body, especially during embryonic development. The exact role of the complex in this pathway is unclear.

Does the IFT122 gene share characteristics with other genes?

The IFT122 gene belongs to a family of genes called IFT (intraflagellar transport homologs). It also belongs to a family of genes called WDR (WD repeat domain containing).

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? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genefamilies) in the Handbook.

How are changes in the IFT122 gene related to health conditions?

cranioectodermal dysplasia - caused by mutations in the IFT122 gene

Mutations in the IFT122 gene can cause cranioectodermal dysplasia. This condition is characterized by an elongated head (dolichocephaly) with a prominent forehead and other distinctive facial features; short bones; and abnormalities of certain tissues known as ectodermal tissues, which include the teeth, hair, nails, and skin.

At least six IFT122 gene mutations have been found in people with cranioectodermal dysplasia. These mutations reduce the amount or function of the IFT122 protein. A shortage or reduction in activity of this component of the IFT-A complex impairs the function of the entire complex, disrupting transport of proteins and materials from the tips of cilia. As a result, assembly and maintenance of cilia is impaired, which leads to a smaller number of cilia and abnormalities in their shape and structure. Although the mechanism is unclear, a loss of normal cilia impedes proper development of bone and other tissues, leading to the features of cranioectodermal dysplasia. Some researchers suggest that disrupted intraflagellar transport prevents signaling through the Sonic Hedgehog pathway, which could impact cell growth and other functions in several tissues throughout the body.

Where is the IFT122 gene located?

Cytogenetic Location: 3q21

Molecular Location on chromosome 3: base pairs 129,440,035 to 129,520,506

The IFT122 gene is located on the long (q) arm of chromosome 3 at position 21.

The IFT122 gene is located on the long (q) arm of chromosome 3 at position 21.

More precisely, the IFT122 gene is located from base pair 129,440,035 to base pair 129,520,506 on chromosome 3.

See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.

Where can I find additional information about IFT122?

You and your healthcare professional may find the following resources about IFT122 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 IFT122 gene or gene products?

  • CED
  • CED1
  • IF122_HUMAN
  • intraflagellar transport 122 homolog (Chlamydomonas)
  • intraflagellar transport protein 122 homolog
  • SPG
  • WDR10
  • WDR10p
  • WDR140
  • WD repeat-containing protein 10
  • WD repeat-containing protein 140
  • WD repeat domain 10

See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What glossary definitions help with understanding IFT122?

cell ; differentiation ; domain ; dysplasia ; embryonic ; gene ; protein ; retina ; tissue

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).

References

  • Arts H, Knoers N. Cranioectodermal Dysplasia. 2013 Sep 12. In: Pagon RA, Adam MP, Ardinger HH, Bird TD, Dolan CR, Fong CT, Smith RJH, Stephens K, editors. GeneReviews® [Internet]. Seattle (WA): University of Washington, Seattle; 1993-2014. Available from http://www.ncbi.nlm.nih.gov/books/NBK154653/. (http://www.ncbi.nlm.nih.gov/pubmed/24027799?dopt=Abstract)
  • OMIM: INTRAFLAGELLAR TRANSPORT 122, CHLAMYDOMONAS, HOMOLOG OF (http://omim.org/entry/606045)
  • Liem KF Jr, Ashe A, He M, Satir P, Moran J, Beier D, Wicking C, Anderson KV. The IFT-A complex regulates Shh signaling through cilia structure and membrane protein trafficking. J Cell Biol. 2012 Jun 11;197(6):789-800. doi: 10.1083/jcb.201110049. (http://www.ncbi.nlm.nih.gov/pubmed/22689656?dopt=Abstract)
  • NCBI Gene (http://www.ncbi.nlm.nih.gov/gene/55764)
  • Qin J, Lin Y, Norman RX, Ko HW, Eggenschwiler JT. Intraflagellar transport protein 122 antagonizes Sonic Hedgehog signaling and controls ciliary localization of pathway components. Proc Natl Acad Sci U S A. 2011 Jan 25;108(4):1456-61. doi: 10.1073/pnas.1011410108. Epub 2011 Jan 5. (http://www.ncbi.nlm.nih.gov/pubmed/21209331?dopt=Abstract)
  • Walczak-Sztulpa J, Eggenschwiler J, Osborn D, Brown DA, Emma F, Klingenberg C, Hennekam RC, Torre G, Garshasbi M, Tzschach A, Szczepanska M, Krawczynski M, Zachwieja J, Zwolinska D, Beales PL, Ropers HH, Latos-Bielenska A, Kuss AW. Cranioectodermal Dysplasia, Sensenbrenner syndrome, is a ciliopathy caused by mutations in the IFT122 gene. Am J Hum Genet. 2010 Jun 11;86(6):949-56. doi: 10.1016/j.ajhg.2010.04.012. Epub 2010 May 20. (http://www.ncbi.nlm.nih.gov/pubmed/20493458?dopt=Abstract)

 

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? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

 
Reviewed: November 2013
Published: November 17, 2014