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 August 2008

What is the official name of the ANOS1 gene?

The official name of this gene is “anosmin 1.”

ANOS1 is the gene's official symbol. The ANOS1 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 ANOS1 gene?

The ANOS1 gene, formerly known as KAL1, provides instructions for making a protein called anosmin-1. This protein is involved in development before birth. Anosmin-1 is located on the surface of cells and may act as part of the extracellular matrix, an intricate lattice of proteins and other molecules that forms in the spaces between cells. Anosmin-1 is found in many parts of the developing embryo, including the respiratory tract, kidneys, digestive system, and certain regions of the brain.

Researchers are working to determine the functions of anosmin-1. They have discovered that, in the developing brain, this protein is involved in the movement (migration) of nerve cells and the outgrowth of axons, which are specialized extensions of nerve cells that transmit nerve impulses. The protein's structure suggests that it may also play a role in regulating contact between nerve cells (cell adhesion).

Anosmin-1 appears to help control the growth and migration of a group of nerve cells that are specialized to process smells (olfactory neurons). These nerve cells come together into a bundle called the olfactory bulb, which is critical for the perception of odors. Studies suggest that anosmin-1 is also involved in the migration of neurons that produce a hormone called gonadotropin-releasing hormone (GnRH). GnRH controls the production of several other hormones that direct sexual development before birth and during puberty. These hormones are important for the normal function of the gonads (ovaries in women and testes in men).

Does the ANOS1 gene share characteristics with other genes?

The ANOS1 gene belongs to a family of genes called fibronectin type III domain containing (fibronectin type III 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? in the Handbook.

How are changes in the ANOS1 gene related to health conditions?

Kallmann syndrome - caused by mutations in the ANOS1 gene

At least 60 mutations in the ANOS1 gene have been identified in people with Kallmann syndrome type 1. In some cases, mutations delete part or all of the ANOS1 gene. Other mutations change single protein building blocks (amino acids) in anosmin-1 or alter the size of the protein. Although ANOS1 gene mutations disrupt the protein's normal function during embryonic development, it is unclear how these genetic changes lead to the characteristic features of Kallmann syndrome.

Researchers suspect that the altered anosmin-1 protein is unable to direct the migration of olfactory nerve cells and GnRH-producing nerve cells to their usual locations in the developing brain. If olfactory nerve cells do not extend to the olfactory bulb, a person's sense of smell will be impaired. Misplacement of GnRH-producing neurons prevents the production of certain sex hormones, which interferes with normal sexual development and causes puberty to be delayed or absent.

It is unknown how ANOS1 gene mutations lead to other signs and symptoms of Kallmann syndrome, including a failure of one kidney to develop (unilateral renal agenesis), hearing loss, and mirror movements of the hands (bimanual synkinesia). Because the features of this condition vary among individuals, researchers believe that additional genetic and environmental factors are likely to be involved.

Where is the ANOS1 gene located?

Cytogenetic Location: Xp22.32

Molecular Location on the X chromosome: base pairs 8,528,874 to 8,732,186

The ANOS1 gene is located on the short (p) arm of the X chromosome at position 22.32.

The ANOS1 gene is located on the short (p) arm of the X chromosome at position 22.32.

More precisely, the ANOS1 gene is located from base pair 8,528,874 to base pair 8,732,186 on the X chromosome.

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

Where can I find additional information about ANOS1?

You and your healthcare professional may find the following resources about ANOS1 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 ANOS1 gene or gene products?

  • adhesion molecule-like X-linked
  • anosmin-1
  • HHA
  • KAL
  • KAL1
  • KALIG-1
  • Kallmann syndrome 1 protein
  • Kallmann syndrome 1 sequence
  • Kallmann syndrome protein
  • KMS
  • WFDC19

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 ANOS1?

acids ; adhesion molecule ; agenesis ; axons ; cell ; cell adhesion ; digestive ; digestive system ; embryo ; embryonic ; extracellular ; extracellular matrix ; gene ; hormone ; kidney ; molecule ; olfactory bulb ; perception ; protein ; puberty ; renal ; respiratory ; syndrome ; synkinesia ; testes ; unilateral

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

See also Understanding Medical Terminology.

References (14 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: August 2008
Published: November 23, 2015