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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 2013

What is the official name of the WDR35 gene?

The official name of this gene is “WD repeat domain 35.”

WDR35 is the gene's official symbol. The WDR35 gene is also known by other names, listed below.

What is the normal function of the WDR35 gene?

The WDR35 gene (also known as IFT121) 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 WDR35 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 WDR35 gene share characteristics with other genes?

The WDR35 gene 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? ( in the Handbook.

How are changes in the WDR35 gene related to health conditions?

cranioectodermal dysplasia - caused by mutations in the WDR35 gene

The WDR35 gene is the most commonly mutated gene in people with cranioectodermal dysplasia; at least eight mutations in this gene have been identified in affected individuals. 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.

The WDR35 gene mutations involved in cranioectodermal dysplasia reduce the amount of functional WDR35 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.

other disorders - caused by mutations in the WDR35 gene

WDR35 gene mutations can cause short-rib polydactyly type 5, a severe condition with signs and symptoms similar to those of cranioectodermal dysplasia (described above); however, affected individuals do not survive to birth. Bone abnormalities in short-rib polydactyly type 5 include extremely short ribs, short arms and legs, and extra fingers or toes (polydactyly). Additional features include abnormalities in one or more organs, including the heart, kidneys, liver, and intestines. The severity of this condition is thought to be caused by a severe loss of function of the WDR35 protein, which likely disrupts the function of cilia to a greater degree than in cranioectodermal dysplasia.

Where is the WDR35 gene located?

Cytogenetic Location: 2p24.1

Molecular Location on chromosome 2: base pairs 19,910,259 to 19,990,122

The WDR35 gene is located on the short (p) arm of chromosome 2 at position 24.1.

The WDR35 gene is located on the short (p) arm of chromosome 2 at position 24.1.

More precisely, the WDR35 gene is located from base pair 19,910,259 to base pair 19,990,122 on chromosome 2.

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

Where can I find additional information about WDR35?

You and your healthcare professional may find the following resources about WDR35 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 WDR35 gene or gene products?

  • CED2
  • IFT121
  • IFTA1
  • intraflagellar transport protein 121 homolog
  • KIAA1336
  • MGC33196
  • naofen
  • WD repeat-containing protein 35

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

What glossary definitions help with understanding WDR35?

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

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


  • 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 (
  • Bacino CA, Dhar SU, Brunetti-Pierri N, Lee B, Bonnen PE. WDR35 mutation in siblings with Sensenbrenner syndrome: a ciliopathy with variable phenotype. Am J Med Genet A. 2012 Nov;158A(11):2917-24. doi: 10.1002/ajmg.a.35608. Epub 2012 Sep 17. (
  • 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. (
  • Mill P, Lockhart PJ, Fitzpatrick E, Mountford HS, Hall EA, Reijns MA, Keighren M, Bahlo M, Bromhead CJ, Budd P, Aftimos S, Delatycki MB, Savarirayan R, Jackson IJ, Amor DJ. Human and mouse mutations in WDR35 cause short-rib polydactyly syndromes due to abnormal ciliogenesis. Am J Hum Genet. 2011 Apr 8;88(4):508-15. doi: 10.1016/j.ajhg.2011.03.015. (
  • NCBI Gene (


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 2013
Published: March 23, 2015