Skip Navigation
Genetics Home Reference: your guide to understanding genetic conditions About   Site Map   Contact Us
Home A service of the U.S. National Library of Medicine®
Printer-friendly version


Reviewed January 2014

What is the official name of the PITX2 gene?

The official name of this gene is “paired like homeodomain 2.”

PITX2 is the gene's official symbol. The PITX2 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 PITX2 gene?

The PITX2 gene provides instructions for making a protein that attaches (binds) to specific regions of DNA and regulates the activity of other genes. On the basis of this action, the PITX2 protein is called a transcription factor. The PITX2 gene is part of a family of homeobox genes, which act during early embryonic development to control the formation of many parts of the body.

The PITX2 protein plays a critical role in early development, particularly in the formation of structures in the front part of the eye (the anterior segment). These structures include the colored part of the eye (the iris), the lens of the eye, and the clear front covering of the eye (the cornea). Studies suggest that the PITX2 protein also has functions in the adult eye, such as helping cells respond to oxidative stress. Oxidative stress occurs when unstable molecules called free radicals accumulate to levels that can damage or kill cells.

The PITX2 protein is also involved in the normal development of other parts of the body, including the teeth, heart, and abdominal organs.

Does the PITX2 gene share characteristics with other genes?

The PITX2 gene belongs to a family of genes called homeobox (homeoboxes).

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 PITX2 gene related to health conditions?

Axenfeld-Rieger syndrome - caused by mutations in the PITX2 gene

More than 45 mutations in the PITX2 gene have been found to cause Axenfeld-Rieger syndrome type 1, a condition that affects the development of the anterior segment of the eye and other parts of the body. Most PITX2 gene mutations reduce the amount of functional PITX2 protein that is produced in cells. However, some genetic changes (such as a duplication of the PITX2 gene) increase the amount or function of the PITX2 protein. Having either too little or too much of this protein disrupts the regulation of other genes needed for normal development.

Eye development appears to be the most sensitive to changes in PITX2 protein activity, and abnormalities of the anterior segment of the eye are the predominant features of Axenfeld-Rieger syndrome. However, changes in the amount of PITX2 protein can also lead to distinctive facial features, tooth abnormalities, and problems with development of other parts of the body in people with this condition.

Peters anomaly - caused by mutations in the PITX2 gene

At least one mutation in the PITX2 gene has been found to cause Peters anomaly. This condition is characterized by abnormal development of the anterior segment of the eye and clouding of the cornea. This mutation (written IVS3AS,A>T,-2) alters the way the PITX2 protein is pieced together. It is thought that this altered protein disrupts the regulation of movement of cells to their proper location in the developing anterior segment, leading to abnormal formation of the structures in this area of the eye and other features of Peters anomaly.

other disorders - caused by mutations in the PITX2 gene

Mutations in the PITX2 gene have also been identified in other eye disorders. Like Axenfeld-Rieger syndrome and Peters anomaly, these conditions primarily involve the anterior segment of the eye. Mutations in the PITX2 gene can cause ring dermoid of the cornea, a condition associated with tumor-like growths on the cornea. Additionally, conditions that cause underdevelopment of the iris can occur, including iris hypoplasia or iridogoniodysgenesis type 2. Iridogoniodysgenesis type 2 is also associated with an elevated risk of increased pressure in the eye (glaucoma).

Where is the PITX2 gene located?

Cytogenetic Location: 4q25

Molecular Location on chromosome 4: base pairs 110,617,423 to 110,642,123

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

The PITX2 gene is located on the long (q) arm of chromosome 4 at position 25.

The PITX2 gene is located on the long (q) arm of chromosome 4 at position 25.

More precisely, the PITX2 gene is located from base pair 110,617,423 to base pair 110,642,123 on chromosome 4.

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

Where can I find additional information about PITX2?

You and your healthcare professional may find the following resources about PITX2 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 PITX2 gene or gene products?

  • all1-responsive gene 1
  • ARP1
  • Brx1
  • IDG2
  • IGDS
  • IGDS2
  • IHG2
  • IRID2
  • Otlx2
  • paired-like homeodomain 2
  • paired-like homeodomain transcription factor 2
  • pituitary homeobox 2
  • PTX2
  • RGS
  • RIEG
  • RIEG1
  • rieg bicoid-related homeobox transcription factor 1
  • RS
  • solurshin

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 PITX2?

anterior ; cornea ; DNA ; duplication ; embryonic ; free radicals ; gene ; glaucoma ; homeobox ; homeodomain ; hypoplasia ; mutation ; oxidative stress ; protein ; stress ; syndrome ; transcription ; transcription factor ; tumor

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

See also Understanding Medical Terminology.

References (11 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 2014
Published: February 8, 2016