Wednesday, October 24, 2012

Type/ Epidermolysis Bullosa Simplex (EBS)

Before we move into more details of the genetic of each type & sub-type of Epidermolysis Bullosa (EB) let’s take a brief idea about each type.

 Epidermolysis Bullosa Simplex (EBS)

Epidermolysis Bullosa Simplex (EBS) is the most common and generally mildest form usually begins at birth or during early infancy. EBS is a collection of keratin disorders characterized by intraepidermal blistering with relatively mild internal involvement. Lesions typically heal without scarring. In EBS, mainly the palms of hands and soles of feet are affected. In EBS, the mutated genes are those involved in the production of keratin, a fibrous protein in the top layer of skin. The condition causes the skin to split in the epidermis, which produces blisters, usually scar formation.
Epidermolysis Bullosa Simplex (EBS) is inherited as autosomal dominant pattern. As we discussed earlier for EBS one single mutated gene from any of the parents is enough to develop the symptoms. However, if the parental condition is mild, there is a chance that EBS may not be diagnosed.
Occasionally, EBS may be the first in one’s family to be affected. In these cases, the mutation will have occurred in the womb before the child was born ~ neither of the parents carries the mutation and the child has a new mutation.
After that if EBS first generation go onto have children, they will have a 50% chance of developing Epidermolysis Bullosa Simplex (EBS).
The more severe Epidermolysis Bullosa Simplex (EBS) subtypes include Koebner, Dowling-Meara, and Weber-Cockayne forms.

Mild Epidermolysis Bullosa Simplex

Weber-Cockayne subtype is the most common form of Epidermolysis Bullosa Simplex (EBS). Blisters usually are precipitated by a clearly identified traumatic event. They can be mild to severe and most frequently occur on the palms and soles. ‘Hyperhidrosis’ can accompany this disorder.

Epidermolysis Bullosa Simplex, Weber-Cockayne subtype.
This mild bullous disease is characterized by localized blistering at sites of trauma such as the feet.

Severe Epidermolysis Bullosa Simplex

Usually, a generalized onset of blisters occurs at or shortly after birth. Hands, feet, and extremities are the most common sites of involvement. Palmoplantar hyperkeratosis and erosions are common, especially in Koebner epidermolysis bullosa simplex.
Dowling-Meara epidermolysis bullosa simplex involves more oral mucosa and manifests with grouped herpetiform blisters (hence the term epidermolysis bullosa simplex herpetiformis).

Epidermolysis Bullosa Simplex, Koebner subtype.

Palmoplantar blistering and hyperkeratosis are noted.

Epidermolysis Bullosa Simplex, Koebner subtype.
Close-up image shows hyperkeratotic papules and plaques on the palm.

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