Meyahealth
HomeGeneticsGenePAX3 gene
Back to Gene
PAX3 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

PAX3 gene

The PAX3 gene acts as a transcription factor essential for embryonic development, particularly in the formation of nerve tissue, pigment cells, and muscles.

Normal Function

The PAX3 gene belongs to the PAX family of genes, which provide instructions for making transcription factors—proteins that bind to specific DNA areas to control the activity of other genes. During embryonic development, PAX3 is active in neural crest cells, which migrate from the spinal cord to form specialized tissues, including nerve tissue and melanocytes (pigment-producing cells). Melanocytes contribute to hair, skin, and eye color, and are also found in the inner ear and brain. Additionally, PAX3 is necessary for the development of craniofacial bones and muscle tissue (myogenesis).

Health Conditions Related to Genetic Changes

Craniofacial-deafness-hand syndrome

Variants in PAX3 can lead to this condition, which is characterized by profound hearing loss, distinctive facial features, and hand muscle abnormalities. A specific variant (Asn47Lys) impairs the protein's ability to bind to DNA, preventing it from directing neural crest cells to form specialized tissues correctly.

Waardenburg syndrome

PAX3 variants are associated with Waardenburg syndrome types I and III. These mutations prevent the PAX3 protein from regulating gene activity, which disrupts the development of melanocytes. This leads to the characteristic patchy loss of pigmentation and hearing loss. Type III may also involve arm and hand abnormalities due to disrupted bone and muscle development.

Cancers

Rearrangements of the PAX3 gene are associated with certain cancers:

  • Alveolar rhabdomyosarcoma: The PAX3 gene fuses with the FOXO1A gene. The resulting fusion protein is overactive, promoting uncontrolled muscle cell growth and preventing cell death.
  • Biphenotypic sinonasal sarcoma: The PAX3 gene fuses with the MAML3 gene. This fusion protein turns on genes involved in nasal passage development abnormally, leading to tumor formation.

Other Names for This Gene

  • CDHS
  • HUP2
  • paired box gene 3 (Waardenburg syndrome 1)
  • paired box homeotic gene 3
  • paired domain gene 3
  • paired domain gene HuP2
  • PAX3/FKHR fusion gene
  • PAX3_HUMAN
  • WS1

Frequently Asked Questions

In alveolar rhabdomyosarcoma, a specific chromosomal rearrangement fuses the PAX3 gene with the FOXO1A gene. This creates an abnormal fusion protein that is constitutively active, meaning it is always on. Unlike the normal PAX3 protein, which regulates specific developmental stages, this fusion protein drives uncontrolled cell growth and prevents programmed cell death (apoptosis) in muscle precursor cells, leading to tumor formation.
Both types involve PAX3 mutations that disrupt melanocyte development, leading to hearing loss and pigmentary changes like a white forelock or heterochromia. However, type III is distinguished by significant limb abnormalities, specifically affecting the arms and hands. These may include contractures, shortening of the forearm, or other skeletal and muscular defects in the upper limbs, which are not present in type I.
Yes, specific variants such as the Asn47Lys mutation can cause craniofacial-deafness-hand syndrome. This condition is characterized by profound hearing loss, distinctive facial features, and hand muscle abnormalities. It is distinct from Waardenburg syndrome because it typically does not present with the patchy loss of pigmentation or white forelock associated with melanocyte defects.
During embryonic development, PAX3 is active in neural crest cells that migrate to form specialized tissues, including those in the inner ear. The protein acts as a transcription factor to regulate genes necessary for the proper formation of auditory structures. When PAX3 function is impaired by mutation, the development of these structures is disrupted, resulting in sensorineural hearing loss, which is a hallmark of associated syndromes.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

Meyahealth

Ⓒ 2026. All rights reserved by MEYA

About UsTerms & PolicyFAQ