EB simplex

About EB simplex (EBS)

Every person has two copies of each gene, the gene mutation that causes EB can be in one or both genes in a pair. However, EBS is usually inherited dominantly, meaning that only one of the genes in a pair is affected.

Dominant types of EB are usually less severe than recessive, hence why EBS is usually less severe than other types, although there are some rare recessive forms of EBS.

This type of EB can comprise three main subtypes:

• Localised EBS (previously known as Weber-Cockayne)
• Intermediate EBS (previously known as EBS generalised intermediate, EBS Köbner)
• Severe EBS (previously known as EBS generalised severe, EBS Dowling-Meara)

DEBRA International, the central body of a worldwide network of EB charities provides a list of all rare subtypes here.

Source: DEBRA International

What are the symptoms of EBS?

Symptoms can vary widely among those affected and impacted by EB, but typically blistering is confined to the hands and feet and the blisters can heal without leaving scars, which is not the case for other types of EB, but hyperpigmentation (darkening of the skin) can occur where the blister was.

• Blistering happens in the upper layer of the skin causing erosions and crusts.
• Blistering and the associated itching can be made worse by heat, humidity and sweating.
• Hyperkeratosis (thickening of the skin) can occur which may affect mobility, nail dystrophy (distortion and discolouration) and milia (small white bumps) are also common in EBS.
• Blistering tends to decrease during adolescence when it may only appear on the hands and feet.
• Milia (small, hard, pale nodules) may appear in the first weeks of life and EB naevi (birthmarks or moles) are common.
• Plantar keratoderma (the thickening of the skin on the soles of the feet) develops gradually, which can be painful and reduce mobility.
• Nails may be thick and dystrophic (appear damaged, misshapen, discoloured, and curvy), particularly in EBS severe.
• Hair is not affected

How is it inherited?

EB is a genetic condition. Genes determine characteristics such as eye colour and also our health. A genetic mutation means a change similar to a spelling mistake has happened and this change makes the gene faulty. We have two copies of every gene, each inherited from one of our parents.

EB simplex is almost exclusively a dominantly inherited condition. This means that one parent has EB simplex. The other parent is usually unaffected. Each time the affected parent has a child there is a one in two chance that the child will be affected. There is no carrier status in a dominantly inherited condition.

Sometimes an affected baby is born to unaffected parents. This is the result of what is called a ‘new mutation’. The problem lies in the genes that hold the instructions necessary for production of certain proteins in the skin. These instructions have a fault, rather like a typing error, with the result that the proteins are incorrectly formed, and unable to fulfil their role in attaching the layers of skin together.

Treatments

There is currently no cure for EB, our work aims to change this. However, there are treatments available which help with the management of pain and itch.

We fund research projects aiming to find additional treatments as well as a cure, and our EB Support Team are committed to help people and carers deal with the challenges that EB brings.