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Genetics Home Reference: your guide to understanding genetic conditions
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DCX

Reviewed July 2013

What is the official name of the DCX gene?

The official name of this gene is “doublecortin.”

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

What is the normal function of the DCX gene?

The DCX gene provides instructions for producing a protein called doublecortin. This protein is involved in the movement of nerve cells (neurons) to their proper locations in the developing brain, a process called neuronal migration. Doublecortin attaches (binds) to microtubules, which are rigid, hollow fibers that make up the cell's structural framework (the cytoskeleton). The binding of doublecortin promotes the stability of microtubules. Microtubules help propel neurons by forming scaffolding within the cell that elongates in a specific direction, altering the cytoskeleton and moving the neuron.

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

isolated lissencephaly sequence - caused by mutations in the DCX gene

More than 70 mutations in the DCX gene have been found to cause isolated lissencephaly sequence (ILS). This condition is characterized by abnormal brain development that results in the brain having a smooth appearance (lissencephaly) instead of its normal folds and grooves. Individuals with ILS have severe neurological problems, including intellectual disability and recurrent seizures (epilepsy) that begin in infancy. Most of the DCX gene mutations that cause ILS change a single protein building block (amino acid) in doublecortin and usually result in a protein with little or no function. A lack of normal doublecortin affects the stability and organization of microtubules, impairing their ability to move cells. Neurons in the developing brain are particularly affected, resulting in the neurological problems associated with ILS.

other disorders - caused by mutations in the DCX gene

Mutations in the DCX gene can cause a condition called subcortical band heterotopia, which is characterized by abnormal brain development, often less severe than ILS (described above). Subcortical band heterotopia occurs when neurons migrate to an area of the brain where they are not supposed to be (heterotopia), and form band-like clusters of white tissue. Since these bands are located beneath an area of the brain known as the cerebral cortex, they are said to be subcortical. The symptoms of subcortical band heterotopia depend on the severity of the brain abnormalities and can vary from severe intellectual disability and epilepsy to normal intelligence with mild or no epilepsy.

Subcortical band heterotopia usually affects females with a mutation affecting one copy of the DCX gene in each cell, while males with one DCX gene mutation usually have ILS. Females can develop ILS and males can develop subcortical band heterotopia, but these instances are rare.

Where is the DCX gene located?

Cytogenetic Location: Xq22.3-q23

Molecular Location on the X chromosome: base pairs 111,293,778 to 111,412,231

The DCX gene is located on the long (q) arm of the X chromosome between positions 22.3 and 23.

The DCX gene is located on the long (q) arm of the X chromosome between positions 22.3 and 23.

More precisely, the DCX gene is located from base pair 111,293,778 to base pair 111,412,231 on the X chromosome.

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 DCX?

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

  • DBCN
  • DC
  • DCX_HUMAN
  • doublecortex
  • doublecortex; lissencephaly, X-linked (doublecortin)
  • lissencephalin-X
  • LISX
  • SCLH
  • XLIS

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 DCX?

amino acid ; cell ; cerebral cortex ; cytoskeleton ; disability ; epilepsy ; gene ; mutation ; neurological ; neuron ; neuronal migration ; protein ; subcortical ; 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

  • OMIM: DOUBLECORTIN (http://omim.org/entry/300121)
  • Forman MS, Squier W, Dobyns WB, Golden JA. Genotypically defined lissencephalies show distinct pathologies. J Neuropathol Exp Neurol. 2005 Oct;64(10):847-57. (http://www.ncbi.nlm.nih.gov/pubmed/16215456?dopt=Abstract)
  • Friocourt G, Marcorelles P, Saugier-Veber P, Quille ML, Marret S, Laquerrière A. Role of cytoskeletal abnormalities in the neuropathology and pathophysiology of type I lissencephaly. Acta Neuropathol. 2011 Feb;121(2):149-70. doi: 10.1007/s00401-010-0768-9. Epub 2010 Nov 3. Review. (http://www.ncbi.nlm.nih.gov/pubmed/21046408?dopt=Abstract)
  • Leventer RJ, Pilz DT, Matsumoto N, Ledbetter DH, Dobyns WB. Lissencephaly and subcortical band heterotopia: molecular basis and diagnosis. Mol Med Today. 2000 Jul;6(7):277-84. Review. (http://www.ncbi.nlm.nih.gov/pubmed/10859564?dopt=Abstract)
  • Liu JS. Molecular genetics of neuronal migration disorders. Curr Neurol Neurosci Rep. 2011 Apr;11(2):171-8. doi: 10.1007/s11910-010-0176-5. Review. (http://www.ncbi.nlm.nih.gov/pubmed/21222180?dopt=Abstract)
  • Matsumoto N, Leventer RJ, Kuc JA, Mewborn SK, Dudlicek LL, Ramocki MB, Pilz DT, Mills PL, Das S, Ross ME, Ledbetter DH, Dobyns WB. Mutation analysis of the DCX gene and genotype/phenotype correlation in subcortical band heterotopia. Eur J Hum Genet. 2001 Jan;9(1):5-12. (http://www.ncbi.nlm.nih.gov/pubmed/11175293?dopt=Abstract)
  • NCBI Gene (http://www.ncbi.nlm.nih.gov/gene/1641)

 

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: July 2013
Published: October 20, 2014