Harlequin type ichthyosis

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**Harlequin type ichthyosis**
*Classifications and external resources*
ICD-10	Q80.4
ICD-9	757.1

Harlequin-type ichthyosis (also harlequin ichthyosis, ichthyosis congenita, or keratosis diffusa fetalis), a skin disease, is the most severe form of congenital ichthyosis, characterized by a thickening of the keratin layer in fetal human skin. In sufferers of the disease, the skin appears as massive, diamond-shaped scales. In addition, the eyes, ears, mouth, and other appendages may be abnormally contracted. The scaly keratin greatly limits the child's movement. Because the skin is cracked where normal skin would fold, it is easily pregnable by bacteria and other contaminants, resulting in serious risk of fatal infection.

Sufferers are known as harlequin fetuses, harlequin babies, or harlequins.

The harlequin-type designation comes from both the baby's apparent facial expression and the diamond-shape of the scales (resembling the costume of Arlecchino), which are caused by severe hyperkeratosis. Seventeenth century entertainers known as jesters, or harlequins, wore costumes with diamond patterns on them, as well as a particular style of face paint. The disease can be diagnosed in the womb by way of fetal skin biopsy or by morphologic analysis of amniotic fluid cells obtained by amniocentesis. Also, doctors can now usually recognize common features of the disease through ultrasound.

1 Features
2 Treatment and prognosis
3 Notable cases
- 3.1 United Kingdom
- 3.2 USA
4 Genetics
5 History
6 Internet
7 References
8 External links

[edit] Features

The features of sufferers are deformed facially and cranially. The ears may be very poorly developed or absent entirely, as may the nose. The eyelids are severely inverted (ectropion), which leaves the eyes and the area around them very susceptible to trauma. They often bleed upon birth. The lips, pulled by the dry skin, are fixed into the semblance of a clown's smile (Eclabium), which many find extremely disconcerting. Arms, feet, and fingers are almost always deformed in such a way that they cannot bend properly, and may be below the normal size. Polydactyly, a condition in which one has more than the usual number of toes or fingers, has also been found in these infants.

They are extremely susceptible to changes in temperature due to their plated skin, which prevents normal heat loss. This can result in hyperthermia. Their respiration is also restricted by the skin, which impedes the chest wall from expanding and drawing in enough air. This can lead to hyperventilation and respiratory failure. Harlequins are often dehydrated, as their plated skin is not well suited to keeping water in.

[edit] Treatment and prognosis

In the past, the disorder was invariably fatal, whether due to dehydration, infection(sepsis), restricted respiration due to the plating, or other related causes. The most common cause of death was systemic infection, and few sufferers survived for more than a few days. However, there have been improvements in care, most notably the drug Isotrex, and some patients have survived into adolescence and, in very rare cases, to adulthood.

[edit] Notable cases

[edit] United Kingdom

A Real Families documentary broadcast on ITV1 in the United Kingdom in 2005 (and later rebroadcast in other countries) showed the lives of two pairs of sisters afflicted with the condition: Lucy Betts and Hannah (aged 18 and 15), and Dana Bowen and Lara (aged 8 and 1½). The girls all went through a daily routine of getting up in the small hours of the morning and bathing for two hours to soften the skin, scrubbing hard to remove as much of the hard extra skin as possible, and then covering their entire bodies in a thick layer of moisturiser. A second and third "creaming" as they called it had to be performed in the afternoon and at bedtime to soften the skin. Even with this treatment a thick layer of hyperkeratotic skin covered them and they were plagued with infections. Scales on the inside of the eyelids had blinded one of Lucy's eyes and left the other eye with 10% vision. Hannah Betts was also a victim of cerebral palsy. Their skin was said to grow at fourteen times the normal rate. Vacuuming the carpets was necessary at least a couple of times a day to remove the shed skin. [1]

The children were said to be four of just seven in the United Kingdom, Lucy being the longest surviving of any such child in the country ever. The chances of suffering from the condition were given as roughly one in a million in general, and exactly one in four in families already with one such child. These figures would indicate that one in 500 people have the recessive gene, giving a one-in-250,000 chance of two unrelated people bringing these genes together, and finally there being a one-in-four chance of these genes being brought together and causing the condition.

Despite the high chance of bringing forth a second baby with the painful condition, both families decided to gamble on having another baby, with the result that a second such baby was indeed born. Furthermore, despite the fact that their daughters were carrying the gene and thus had at least a one-in-2000 (instead of one-in-1,000,000) chance of having harlequin babies themselves (and also passing this increased probability to future generations), the parents of Lucy in particular were keen on her marrying and having children.

[edit] USA

In San Diego, there is a young man named Ryan González who has this condition. Ryan has not only survived to adulthood but also thrives as a triathlete. A true accomplishment indeed, by any standards. His treatment involves dosing with isotretinoin (also known as Accutane), the constant use of lotions to keep the skin supple, and use of a very high-calorie diet of at least 7,500 calories a day, including a nightly feeding tube of pure protein due the constant shedding of the skin, believed to shed seven to ten times faster than unaffected skin.

Ryan takes part in the triathlon for athletes with disabilities and swims regularly. [2]

[edit] Genetics

Mutations in the ABCA12 gene cause harlequin ichthyosis. The ABCA12 gene makes a protein that is essential for the normal development of skin cells. Although the protein's exact function is unknown, researchers believe that it probably plays a major role in the transport of lipids (fats) in the outermost layer of skin (the epidermis). Mutations in the ABCA12 gene lead to the production of an abnormally small version of the protein that cannot transport lipids properly. The loss of functional ABCA12 protein disrupts the normal development of the epidermis, preventing the skin from forming an effective barrier and resulting in the hard, thick scales characteristic of harlequin ichthyosis.

This condition is likely inherited in an autosomal recessive pattern, which means two copies of the gene in each cell are altered. Most often, the parents of an individual with an autosomal recessive disorder are carriers of one copy of the altered gene but do not show signs and symptoms of the disorder.

[edit] History

The disease has been known since around 1750, and was first described in the diary of Rev. Oliver Hart:

"On Thursday, April ye 5, 1750, I went to see a most deplorable object of a child, born the night before of one Mary Evans in 'Chas'town. It was surprising to all who beheld it, and I scarcely know how to describe it. The skin was dry and hard and seemed to be cracked in many places, somewhat resembling the scales of a fish. The mouth was large and round and open. It had no external nose, but two holes where the nose should have been. The eyes appeared to be lumps of coagulated blood, turned out, about the bigness of a plum, ghastly to behold. It had no external ears, but holes where the ears should be. The hands and feet appeared to be swollen, were cramped up and felt quite hard. The back part of the head was much open. It made a strange kind of noise, very low, which I cannot describe. It lived about forty-eight hours and was alive when I saw it."

More than a hundred cases have been reported worldwide in modern times. Neither gender nor race seem to affect the likelihood of a child having the disorder. A disproportionately high number of children have consanguineous parents. Those from families with a history of severe skin disorders may have a higher risk of birthing a harlequin child.

[edit] Internet

Babies afflicted with this disease have a most unusual appearance, which many find distressing. For this reason, websites with photographs of such babies are often linked to on Internet forums by Internet trolls as a form of shock site, even though many are medical websites and not intended for this purpose. Some of these photos have been included in the notorious Pain Series of shock image collages. A series of photos claiming to show the effects of depleted uranium in Iraq includes a picture of a child with harlequin ichthyosis. Critics of the photos question whether the photo was from Iraq, let alone whether the case was caused by depleted uranium.

[edit] References

Sheila Au, MD, Julie Prendiville, MD. (2004). eMedicine Specialties > Dermatology > Pediatric Diseases. Retrieved Jan. 20, 2004 from http://www.emedicine.com/derm/topic192.htm
Akiyama M (1999). "The pathogenesis of severe congenital ichthyosis of the neonate". J Dermatol Sci 21 (2): 96-104. PMID 10511478.
Kelsell DP, Norgett EE, Unsworth H, Teh MT, Cullup T, Mein CA, Dopping-Hepenstal PJ, Dale BA, Tadini G, Fleckman P, Stephens KG, Sybert VP, Mallory SB, North BV, Witt DR, Sprecher E, Taylor AE, Ilchyshyn A, Kennedy CT, Goodyear H, Moss C, Paige D, Harper JI, Young BD, Leigh IM, Eady RA, O'Toole EA (2005). "Mutations in ABCA12 underlie the severe congenital skin disease harlequin ichthyosis". Am J Hum Genet 76 (5): 794-803. PMID 15756637.
Moskowitz DG, Fowler AJ, Heyman MB, Cohen SP, Crumrine D, Elias PM, Williams ML (2004). "Pathophysiologic basis for growth failure in children with ichthyosis: an evaluation of cutaneous ultrastructure, epidermal permeability barrier function, and energy expenditure". J Pediatr 145 (1): 82-92. PMID 15238912.