Epidermolysis Bullosa

At a glance

It is defined as a group of genetically inherited connective tissue disorders characterized by cutaneous blistering of the skin and mucosal membranes after minor trauma. The lesions heal with severe scarring. It results from a membrane defect located between the epidermis and the dermis as a result of external shearing forces applied to the skin, such as simple friction. Its severity ranges from mild to lethal.

N.B.: Affected children are often called “Butterfly Children Syndrome” since their skin is known to be as fragile as a butterfly’s wings. Other mention includes the “Cotton Wool Babies” or, as it is often the case in South Africa, they are called “Crystal Skin Children.”

History

The condition was brought to public attention in 2004 in the United Kingdom in a documentary about “The Boy Whose Skin Fell Off,” chronicling the life and death of Jonny Kennedy, an Englishman affected with EB. In the United States, a similar production was presented in 2003 and entitled My Flesh and Blood.

Classification

More than 20 different subtypes of the disease are grouped into three main categories: epidermolysis bullosa simplex (EBS), dystrophic epidermolysis bullosa (DEB), and junctional epidermolysis bullosa (JEB). It is reported that infants affected with epidermolysis bullosa simplex (EBS) and junctional epidermolysis bullosa (JEB) tend to die in infancy and the last group later during adulthood.

• Junctional Epidermolysis Bullosa:

  • Herlitz Type (Lethal Type)

  • Non-Herlitz Type

  • JEB with Pyloric Atresia (☞Carmi Syndrome)

• Epidermolysis Bullosa Simplex:

  • Weber-Cockayne Type

  • Dowling-Mara Type (EBS Herpetiformis)

  • Koebner Type

• Dystrophic Epidermolysis Bullosa

Incidence

An estimated prevalence of 20 individuals per million live births is diagnosed with EB, and 9 per million people in the general population present the symptomatology of the condition. Over a 16 years period (1986-2002), the data from the National Institutes of Health, 3,300 EB patients were identified, enrolled, classified, clinically characterized, and followed for outcomes. The prevalence and incidence of EB was estimated at approximately 8 per one million population and 19 per one million live births in the general population in 1990 and 1986 to 1990, respectively. It is established that approximately 92% are epidermolysis bullosa simplex (EBS), 5% are dystrophic epidermolysis bullosa (DEB), 1% are junctional epidermolysis bullosa (JEB), and 2% remain unclassified. Carrier frequency ranges from 1 in 333 for JEB and up to 1 in 450 for DEB. The carrier frequency for EBS is presumed to be much higher than JEB or DEB. The disorder occurs in every racial and ethnic group and affects both sexes equally. There are 72 families with epidermolysis bullosa (EB) in Romania.

Genetic inheritance

DEB has two modes of transmission that are autosomal dominant and more frequently autosomal recessive. EBS is inherited as an autosomal dominant ...