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.



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.



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