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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®

Hystrix-like ichthyosis with deafness

Reviewed November 2012

What is hystrix-like ichthyosis with deafness?

Hystrix-like ichthyosis with deafness (HID) is a disorder characterized by dry, scaly skin (ichthyosis) and hearing loss that is usually profound. Hystrix-like means resembling a porcupine; in this type of ichthyosis, the scales may be thick and spiky, giving the appearance of porcupine quills.

Newborns with HID typically develop reddened skin. The skin abnormalities worsen over time, and the ichthyosis eventually covers most of the body, although the palms of the hands and soles of the feet are usually only mildly affected. Breaks in the skin may occur and in severe cases can lead to life-threatening infections. Affected individuals have an increased risk of developing a type of skin cancer called squamous cell carcinoma, which can also affect mucous membranes such as the inner lining of the mouth. People with HID may also have patchy hair loss caused by scarring on particular areas of skin.

How common is hystrix-like ichthyosis with deafness?

HID is a rare disorder. Its prevalence is unknown.

What genes are related to hystrix-like ichthyosis with deafness?

HID is caused by mutations in the GJB2 gene. This gene provides instructions for making a protein called gap junction beta 2, more commonly known as connexin 26. Connexin 26 is a member of the connexin protein family. Connexin proteins form channels called gap junctions that permit the transport of nutrients, charged atoms (ions), and signaling molecules between neighboring cells that are in contact with each other. Gap junctions made with connexin 26 transport potassium ions and certain small molecules.

Connexin 26 is found in cells throughout the body, including the inner ear and the skin. In the inner ear, channels made from connexin 26 are found in a snail-shaped structure called the cochlea. These channels may help to maintain the proper level of potassium ions required for the conversion of sound waves to electrical nerve impulses. This conversion is essential for normal hearing. In addition, connexin 26 may be involved in the maturation of certain cells in the cochlea. Connexin 26 also plays a role in the growth and maturation of the outermost layer of skin (the epidermis).

At least one GJB2 gene mutation has been identified in people with HID. This mutation changes a single protein building block (amino acid) in connexin 26. The mutation is thought to result in channels that constantly leak ions, which impairs the health of the cells and increases cell death. Death of cells in the skin and the inner ear may underlie the signs and symptoms of HID.

Because the GJB2 gene mutation identified in people with HID also occurs in keratitis-ichthyosis-deafness syndrome (KID syndrome), a disorder with similar features and the addition of eye abnormalities, many researchers categorize KID syndrome and HID as a single disorder, which they call KID/HID. It is not known why some people with this mutation have eye problems while others do not.

Related Gene(s)

Changes in this gene are associated with hystrix-like ichthyosis with deafness.

  • GJB2

How do people inherit hystrix-like ichthyosis with deafness?

This condition is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder.

In some cases, an affected person inherits the mutation from one affected parent. Other cases result from new mutations in the gene and occur in people with no history of the disorder in their family.

Where can I find information about diagnosis or management of hystrix-like ichthyosis with deafness?

These resources address the diagnosis or management of hystrix-like ichthyosis with deafness and may include treatment providers.

  • Foundation for Ichthyosis and Related Skin Types: Ichthyosis Hystrix (
  • Genetic Testing Registry: Hystrix-like ichthyosis with deafness (

You might also find information on the diagnosis or management of hystrix-like ichthyosis with deafness in Educational resources and Patient support.

General information about the diagnosis ( and management ( of genetic conditions is available in the Handbook. Read more about genetic testing (, particularly the difference between clinical tests and research tests (

To locate a healthcare provider, see How can I find a genetics professional in my area? ( in the Handbook.

Where can I find additional information about hystrix-like ichthyosis with deafness?

You may find the following resources about hystrix-like ichthyosis with deafness helpful. These materials are written for the general public.

You may also be interested in these resources, which are designed for healthcare professionals and researchers.

What other names do people use for hystrix-like ichthyosis with deafness?

  • HID syndrome
  • ichthyosis, hystrix-like, with deafness

For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines ( and How are genetic conditions and genes named? ( in the Handbook.

What if I still have specific questions about hystrix-like ichthyosis with deafness?

Ask the Genetic and Rare Diseases Information Center (

What glossary definitions help with understanding hystrix-like ichthyosis with deafness?

amino acid ; autosomal ; autosomal dominant ; cancer ; carcinoma ; cell ; cochlea ; connexin ; epidermis ; gap junctions ; gene ; ichthyosis ; inherited ; ions ; keratitis ; mucous ; mutation ; potassium ; prevalence ; protein ; syndrome

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


  • Lee JR, White TW. Connexin-26 mutations in deafness and skin disease. Expert Rev Mol Med. 2009 Nov 19;11:e35. doi: 10.1017/S1462399409001276. Review. (
  • Todt I, Hennies HC, Küster W, Smolle J, Rademacher G, Mutze S, Basta D, Eisenschenk A, Ernst A. Neurotological and neuroanatomical changes in the connexin-26-related HID/KID syndrome. Audiol Neurootol. 2006;11(4):242-8. Epub 2006 May 4. (
  • van Geel M, van Steensel MA, Küster W, Hennies HC, Happle R, Steijlen PM, König A. HID and KID syndromes are associated with the same connexin 26 mutation. Br J Dermatol. 2002 Jun;146(6):938-42. (
  • van Steensel MA. Gap junction diseases of the skin. Am J Med Genet C Semin Med Genet. 2004 Nov 15;131C(1):12-9. Review. Erratum in: Am J Med Genet C Semin Med Genet. 2006 Feb 15;142(1):58. (
  • Xu J, Nicholson BJ. The role of connexins in ear and skin physiology - functional insights from disease-associated mutations. Biochim Biophys Acta. 2013 Jan;1828(1):167-78. doi: 10.1016/j.bbamem.2012.06.024. Epub 2012 Jul 13. Review. (


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: November 2012
Published: February 1, 2016