View source for Harlequin-type ichthyosis

'''Harlequin-type ichthyosis''' (pronunciation: har-le-quin type ik-thee-o-sis) is a severe genetic disorder that primarily affects the skin. It is the most severe form of [[congenital ichthyosis]], characterized by a thickening of the [[keratin]] layer in fetal human skin.

==Etymology==
The term "Harlequin" comes from the distinctive diamond-shaped pattern of a Harlequin's costume in Commedia dell'arte, which resembles the thick, hard, diamond-shaped scales that form on the skin of those with the condition. "Ichthyosis" is derived from the Greek "ichthys" meaning fish, referring to the scaly skin seen in this condition.

==Symptoms==
Infants with Harlequin-type ichthyosis are born with very hard, thick skin covering most of their bodies. The skin forms large, diamond-shaped plates that are separated by deep cracks (fissures). These abnormalities affect the shape of the [[eyelids]], [[nose]], [[mouth]], and [[ears]], and limit movement of the arms and legs. Restricted movement of the chest can lead to breathing difficulties and respiratory failure.

==Causes==
Harlequin-type ichthyosis is caused by mutations in the [[ABCA12]] gene. This gene provides instructions for making a protein that is essential for normal skin development. Mutations in the ABCA12 gene disrupt the normal development of the skin, leading to the severe symptoms of Harlequin-type ichthyosis.

==Treatment==
There is no cure for Harlequin-type ichthyosis, but the symptoms can be managed. Treatment typically includes intensive care at birth, frequent application of moisturizers and protective ointments, and in some cases, retinoid drugs.

==Related Terms==
* [[Congenital Ichthyosis]]
* [[Keratin]]
* [[ABCA12]]
* [[Genetic Disorder]]

[[Category:Medical Dictionary]]
[[Category:Genetic Disorders]]
[[Category:Dermatology]]
[[Category:Rare Diseases]]

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