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The official name of this gene is “WD repeat domain 19.”
WDR19 is the gene's official symbol. The WDR19 gene is also known by other names, listed below.
The WDR19 gene (also known as IFT144) 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 WDR19 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.
The WDR19 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? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genefamilies) in the Handbook.
At least two mutations in the WDR19 gene have been found in individuals with 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. Cranioectodermal dysplasia can also cause a variety of other problems, including a kidney condition called nephronophthisis and eye abnormalities.
The WDR19 gene mutations involved in cranioectodermal dysplasia reduce the amount of functional WDR19 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.
Mutations in the WDR19 gene can cause other conditions with features that overlap with those of cranioectodermal dysplasia (described above). Conditions associated with WDR19 gene mutations range from the less severe isolated autosomal recessive retinitis pigmentosa to the more severe Senior-Løken syndrome.
Isolated autosomal recessive retinitis pigmentosa affects the retina and causes blindness. Retinitis pigmentosa can be one of many features in more complex conditions, including cranioectodermal dysplasia, but people diagnosed with isolated autosomal recessive retinitis pigmentosa have no other abnormalities.
Senior-Løken syndrome is characterized by the combination of two specific features: a kidney condition called nephronophthisis and a disorder of the eye called Leber congenital amaurosis. Nephronophthisis causes scarring (fibrosis) in the kidneys and usually leads to impaired kidney function. Leber congenital amaurosis primarily affects the retina and causes vision problems in affected individuals.
The severity of signs and symptoms in the spectrum of conditions caused by WDR19 gene mutations may be associated with the degree of disruption of cilia structure or function.
Cytogenetic Location: 4p14
Molecular Location on chromosome 4: base pairs 39,182,403 to 39,285,809
The WDR19 gene is located on the short (p) arm of chromosome 4 at position 14.
More precisely, the WDR19 gene is located from base pair 39,182,403 to base pair 39,285,809 on chromosome 4.
See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.
You and your healthcare professional may find the following resources about WDR19 helpful.
You may also be interested in these resources, which are designed for genetics professionals and researchers.
See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.
autosomal ; autosomal recessive ; cell ; congenital ; differentiation ; domain ; dysplasia ; embryonic ; fibrosis ; gene ; kidney ; protein ; recessive ; retina ; spectrum ; syndrome ; tissue
You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://ghr.nlm.nih.gov/glossary).
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.