Lamellar Ichthyosis

 

Lamellar Ichthyosis

Lamellar Ichthyosis

 

Lamellar ichthyosis (LI) is a rare genetic skin disorder that is present at birth. It is one of three genetic skin disorders called autosomal recessive congenital ichthyoses (ARCI). The other two are known as harlequin ichthyosis and congenital ichthyosiform erythroderma. All ARCI conditions are considered a clinical spectrum. There is overlap in symptoms between ARCI conditions. In LI, the body creates skin cells at a normal rate. However, they do not separate from each other at the surface of the skin the way they should.

In addition, the body does not shed the skin fast enough, causing brown scales to form.

 

Synonyms

·         collodion baby

·         congenital lamellar ichthyosis

·         LI

 

Signs & Symptoms

Babies born with LI are sometimes called “collodion babies.” They are covered in a clear membrane (collodion) so it looks like they are covered with plastic wrap. Their skin can look red or dark, tight, and split. These newborns can have skin that is so tight that it forces their lips to turn outward. Also, the skin on their hands may be tight, preventing them from extending their fingers. Newborns can have problems regulating their body temperature and preventing water loss. They may also be more likely to develop skin infections. The collodion membrane is usually shed a few days to a few weeks after birth. Once this happens, the newborn is covered with broad, dark scales. The space in between the scales may be shallow or deep.

Some people with LI cannot close their eyes because the skin is so tight. In some cases, the skin around the eyes pulls so tightly that it causes the eyelids to turn outward. It can lead to irritation of the inner eyelid and drying of the eyeball. Some doctors recommend surgery to prevent damage to the eyeball and vision problems. People with LI may also have thick nails and hair loss due to the thickness of the scales on their scalp. They may also have thick skin on the palms of the hands and soles of the feet.

 

Causes

LI can be caused by harmful changes in several genes. The most common gene related to this condition is TGM1. Other genes include NIPAL4, ALOX12B, and CYP4F22. These genes provide the instructions to make enzymes and proteins. These enzymes and proteins are important for normal development, function, and shedding of skin cells. There is also evidence that more genes are related to LI. The severity of the condition cannot always be determined based on genetic testing results.

The harmful changes that cause LI are recessively inherited. Recessive genetic disorders occur when an individual inherits a non-working gene from each parent. If an individual receives one working gene and one non-working gene for the disease, the person will be a carrier for the disease, but usually will not show symptoms. The risk for two carrier parents to both pass the non-working gene and therefore have an affected child is 25% with each pregnancy. The risk to have a child who is a carrier, like the parents, is 50% with each pregnancy. The chance for a child to receive working genes from both parents is 25%. The risk is the same for males and females.

 

Related Disorders

Signs and symptoms of the following disorders may be like those of LI.

“Ichthyoses” are a group of disorders that cause scaly skin. People with ichthyosis have a build-up of large amounts of dead skin cells on the top layer of the skin. This build up can be caused by defects in various structures in the skin. Skin cells known as “corneocytes” make up the outer layer of the skin. These cells are surrounded by proteins that make the skin strong and flexible. Corneocytes are also surrounded by a fat-rich matrix that waterproofs the skin. Corneocytes are connected to each other by proteins. The breakdown of these proteins is important for skin shedding. You can think of the skin cells as bricks, while the surrounding matrix is the mortar holding the cells together. When any of these skin structures are not working, a person can have ichthyosis. (See “Ichthyosis” in the Rare Disease Database.)

Congenital ichthyosiform erythroderma (sometimes called collodion baby, ichthyosis congenita, xeroderma, or desquamation of the newborn) is a genetic skin disorder on the spectrum of ARCI. Symptoms include abnormally red, dry, and rough skin with large or fine white scales. The skin tends to feel itchy as well. Skin on the palms of the hands and soles of the feet can be very thick. (For more information, choose “Ichthyosis Congenita” as your search term in the Rare Disease Database.)

X-linked ichthyosis is a genetic skin disorder that affects mostly males but can affect females. It is caused when people do not have enough of the enzyme steroid sulfatase. Symptoms include brownish scales on the back of the neck, back, and legs.

There are other conditions where ichthyosis is a symptom. However, many of these conditions are syndromic and have other symptoms that do not affect the skin. These symptoms can include cognitive disabilities, nervous system problems, and arm/leg shortening.

 

 

Standard Therapies

Treatment
LI is usually treated topically. Doctors use creams that help repair the skin barrier. These creams often contain ceramides or cholesterol. Moisturizers with petrolatum or lanolin may also be used. Sometimes, mild keratolytics or topical retinoids are used as treatment options. Doctors may treat severe LI with oral retinoids. Retinoids can be toxic to the body, so they are used with caution.

To diagnose and treat ARCI, including LI, people may need to see the following medical specialists:

·         Clinical geneticist and/or genetic counselor

·         Skin doctor (dermatologist) familiar with congenital ichthyosis

·         Eye doctor (ophthalmologist) familiar with congenital ichthyosis

Tests for temperature regulation problems and water loss as well as tests for infection may be needed.