Daniel de Boer, Founder and CEO of ProQR, discussuses Epidermolysis bullosa (EB), a group of genetic skin diseases that cause the skin to blister and erode very easily. In people with EB, blisters form in response to minor injuries or friction, such as rubbing or scratching. There are four main types of EB, which are classified based on the depth, or level, of blister formation:
- Dystrophic epidermolysis bullosa
- Epidermolysis bullosa simplex
- Kindler Syndrome
- Junctional epidermolysis bullosa
EB may then be further classified based on severity and specific symptoms, such as distribution (localized or generalized) and whether parts of the body other than the skin are affected. Specific sub-types may then be determined based on identifying the exact protein that is defective in a person with EB. This may be done by tests performed on a skin biopsy, or when possible, genetic testing. Identifying the exact sub-type can be hard because there are many sub-types of EB. A person with any main type of EB may be mildly or severely affected, and the disease can range from being a minor inconvenience requiring modifying activities, to completely disabling and even fatal in some cases.
There are two main types of DEB – the dominant form (DDEB) when the affected person inherits the altered gene from only one parent and the recessive form (RDEB) when the affected person inherits one copy of the altered gene from each parent. RDEB tends to be generally more severe than DDEB. People with DEB have blistering of skin and mucosal membranes that line many tracts and structures of the body, such as the mouth, food pipe etc. Children with DEB are often called ‘Butterfly children’ as their skin is as fragile as the wings of a butterfly. This fragility results from a very weak connection between the dermis (inner layer) and the epidermis (outer layer) of the skin.
People with DEB live with constant pain and have a high risk of malnutrition and infections. Symptoms include poorly healing wounds, skin infections, fusion of fingers and toes (pseudosyndactyly), anemia, gastrointestinal tract problems and with adulthood some develop very aggressive forms of squamous cell carcinoma (skin cancer).