Hystrix-like ichthyosis–deafness syndrome

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Hystrix-like ichthyosis–deafness syndrome (HID syndrome) is a rare genetic disorder characterized by the presence of ichthyosis and sensorineural hearing loss. This condition is part of a group of disorders known as keratinization disorders, which affect the skin's ability to shed dead cells, leading to thick, scaly skin.

Presentation

Individuals with HID syndrome typically present with ichthyosis, which manifests as thick, spiky scales on the skin, resembling the quills of a porcupine. This distinctive skin condition is often apparent at birth or develops in early childhood. In addition to skin abnormalities, affected individuals experience sensorineural hearing loss, which can range from mild to profound. The hearing loss is usually congenital, meaning it is present from birth.

Genetics

HID syndrome is inherited in an autosomal dominant pattern, meaning a single copy of the altered gene in each cell is sufficient to cause the disorder. The specific gene associated with HID syndrome is GJB2, which encodes the protein connexin 26. Mutations in this gene disrupt the function of connexin 26, leading to the symptoms observed in HID syndrome.

Diagnosis

Diagnosis of HID syndrome is based on clinical evaluation, family history, and genetic testing. The presence of characteristic skin lesions and hearing loss, along with a positive genetic test for mutations in the GJB2 gene, confirms the diagnosis.

Management

There is no cure for HID syndrome, and treatment focuses on managing symptoms. Emollients and keratolytics can help to soften and remove the thickened skin. Regular hearing assessments and the use of hearing aids or other assistive devices can help manage hearing loss. Genetic counseling is recommended for affected individuals and their families.

Prognosis

The prognosis for individuals with HID syndrome varies. While the skin condition and hearing loss are lifelong, they do not typically affect life expectancy. However, the severity of symptoms can impact the quality of life.

See also

• Ichthyosis
• Sensorineural hearing loss
• Keratinization disorders
• GJB2