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GeneDx :: Tests :: Harlequin Ichthyosis (HI), Lamellar ichthyosis, type genedx.com | SMA Clinical Research Center about Type 1, Type 2, Type 3 columbiasma.org |
Not to be confused with Harlequin syndrome.
Harlequin-type ichthyosis (also harlequin ichthyosis, ichthyosis congenita, Ichthyosis fetalis, keratosis diffusa fetalis, and Harlequin fetus[1]:562), 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 contains massive, diamond-shaped scales, and tends to have a reddish color. 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 simply 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. The disease can be diagnosed in the uterus by way of fetal skin biopsy or by morphologic analysis of amniotic fluid cells obtained by amniocentesis. In addition, doctors can now usually recognize common features of the disease through ultrasound, and follow up with 3D ultrasound to diagnose the condition.
[edit] HistoryThe disease has been known since 1750, and was first described in the diary of a cleric from Charleston, South Carolina, the Rev. Oliver Hart:
At least 400 cases have been reported worldwide in modern times.[citation needed] Neither gender nor ethnicity seem to affect the likelihood of a child having the disorder.[citation needed] [edit] FeaturesThe features of the sufferers are severe cranial and facial deformities. The ears may be very poorly developed or absent entirely, as may the nose. The eyelids are severely everted (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 a wide grimace (eclabium). Arms, feet, and fingers are almost always deformed in such a way that they cannot bend properly, and may be below the normal size. They present hypoplasia in the fingers; therefore, they cannot grab things properly, or they can barely touch them. 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 armor-like 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 hypoventilation and respiratory failure. Harlequins are often dehydrated, as their plated skin is not well suited to keeping water in. [edit] Treatment and prognosisIn the past, the disorder was invariably fatal, whether due to dehydration, infection (sepsis), restricted breathing due to the plating, or other related causes. The most common cause of death was systemic infection and sufferers rarely survived for more than a few days. However, there have been improvements in care, most notably the drug Isotretinoin (Isotrex). The eldest known survivor is 24-year old Nusrit "Nelly" Shaheen, who is in good health[3]. Lifespan limitations have not yet been determined with the new treatments. [edit] Notable cases[edit] United KingdomNusrit "Nelly" Shaheen (born 1984) is the oldest survivor with the condition in the UK. She is one of eight children, four of whom also suffered from the condition and died as young children. Nelly lives an active lifestyle and is studying sports coaching and leadership at Hereward College. She hopes to teach the course in the future.[4][5] [edit] See also[edit] Notes
[edit] References
[edit] External linksThe following links may contain graphic or disturbing depictions of the effects of Harlequin type ichthyosis on infants.
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