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MSX1 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

MSX1 gene

The MSX1 gene regulates the activity of other genes and is critical for the normal development of teeth, mouth structures, and potentially fingernails and toenails.

Normal Function

The MSX1 gene provides instructions for making a protein that regulates the activity of other genes. The MSX1 gene is part of a larger family of homeobox genes, which control the formation of many body structures during early development. Specifically, this gene is critical for the normal development of the teeth and other structures in the mouth. It may also be important for the development of fingernails and toenails.

Health Conditions Related to Genetic Changes

Wolf-Hirschhorn syndrome

The MSX1 gene is often deleted in people with Wolf-Hirschhorn syndrome. The features of this condition include a characteristic facial appearance, delayed growth and development, intellectual disability, and seizures.

A loss of the MSX1 gene probably disrupts the regulation of several other genes, particularly genes involved in the development of the mouth and teeth. Researchers believe that a deletion of the MSX1 gene disrupts the formation of oral structures in early development, leading to missing teeth and other dental abnormalities. A loss of the MSX1 gene probably also causes an opening in the roof of the mouth (cleft palate) and/or a split in the upper lip (cleft lip) seen in some people with Wolf-Hirschhorn syndrome.

Other disorders

MSX1 gene variants (also called mutations) are associated with abnormalities of mouth and tooth development. For example, changes in this gene contribute to some cases of cleft lip and/or cleft palate in people who do not have Wolf-Hirschhorn syndrome. MSX1 gene variants appear to be one of many genetic and environmental factors that play a role in oral clefting.

At least six MSX1 gene variants are responsible for oligodontia, a condition in which multiple teeth fail to develop. Some individuals with MSX1 gene variants have a combination of oligodontia and cleft lip and/or cleft palate. Variants in the MSX1 gene likely reduce the amount of functional MSX1 protein within cells, which disrupts the early development of structures in the mouth.

Another variant in the MSX1 gene has been found to cause Witkop syndrome (also known as tooth-and-nail syndrome). This rare condition is characterized by missing teeth and abnormalities of the fingernails and toenails. The MSX1 gene variant mutation responsible for Witkop syndrome leads to the production of an abnormally short, nonfunctional version of the MSX1 protein. A loss of this protein disrupts the formation of the teeth and nails during early development.

Other Names for This Gene

  • homeobox 7
  • homeobox protein MSX-1
  • HOX7
  • HYD1
  • msh homeo box 1
  • MSH Homeo Box Homolog 1 (Drosophila) Gene
  • msh homeobox homolog 1
  • MSX1_HUMAN
  • OFC5

Frequently Asked Questions

Witkop syndrome, also known as tooth-and-nail syndrome, is an autosomal dominant condition caused by mutations in MSX1. It is characterized by the combination of missing permanent teeth (hypodontia) and abnormal development of fingernails and toenails. Nails are often slow-growing, thin, brittle, spoon-shaped (koilonychia), or even spontaneously shed during childhood, though nail appearance frequently improves with age while dental gaps remain permanent.
baseline pediatric dental examination should occur by age one, but specialized screening for tooth agenesis begins around ages 6 to 7 with a panoramic dental radiograph (Orthopantomogram). At this stage, dental specialists can confirm whether permanent tooth buds are present, initiate preventive space-maintenance therapy, and plan a multidisciplinary orthodontic and prosthodontic strategy before facial skeletal growth finishes.
Mutations in the MSX1 gene predominantly cause selective hypodontia or oligodontia, specifically affecting the posterior dentition. The most frequently absent permanent teeth are the second premolars and the third molars (wisdom teeth). In more severe cases, maxillary first premolars and permanent lateral incisors can also fail to form, while primary (baby) teeth are often completely normal.
Pathogenic variants in MSX1 follow an autosomal dominant inheritance pattern. This means an affected parent has a 50 percent chance of passing the variant to each child. However, the gene exhibits variable expressivity and reduced penetrance. A parent with a single missing tooth might have a child who inherits the same mutation and develops multiple missing teeth, an isolated cleft palate, or no dental anomalies at all.
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.

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