Epidermolysis Bullosa, or just EB, is a very rare, genetic connective tissue disorder which is difficult to define in one or two sentences. It encompasses a group of disorders that the share the most prominent, and well known, symptom of extremely fragile skin that blisters and tears with the slightest friction or trauma. The severity of the disorder is dependent upon many factors including type and subtype of EB and the inheritance pattern. In general, the manifestations, symptoms and outcomes range from very mild to severe. In some forms, blistering of the skin may be limited to the hands and feet while not resulting in any scarring or loss of function. In other forms, there is more generalized blistering of the skin and oral cavity as well as injury to many internal organs and bodily systems. Some forms of EB result in disfigurement, disability and early death, while other types can be fatal within the first few months of life.
EB affects both genders as well as every racial and ethnic group equally.
EB is PAINFUL – Wounds caused by the disorder may never heal and they are prone to life threatening infections.
EB is PERVASIVE – It affects internal organs as well as the eyes, nose, mouth, throat and anus. The list of secondary complications is long and requires multiple interventions from a range of medical specialists. Some typical complications complications are: infections, anemia, failure to thrive, growth retardation, inability to swallow, corneal abrasions, contractures, depression, anxiety, malnutrition, constipation, premature tooth decay and a particularly virulent form of cancer.
EB is DEBILITATING – In some forms of EB repeated injury and scarring lead to deformity and lack of function in the hands, in the feet and in the mouth.
EB is LETHAL – Some will lose their battle in the first year of life, others may succumb to squamous cell carcinoma in their teens, others from bacterial sepsis (blood infection), cardiomyopathy, renal failure, or dehydration to name a few causes.
WHAT CAUSES EB?
In all its forms, EB is caused by a mutation in the DNA code in genes that produce proteins. The mutations may result in the inability to produce any of a required protein or it may result in the incorrect formation of a protein. Either way, the protein whether that be keratin, collagen, plectin or laminin, does not work properly.
Recessive Dystrophic EB – Rafi’s Diagnosis
In Rafi’s case, her body, before transplant, did not produce Collagen 7, the primary building block of something called anchoring fibrils. Think of Rafi’s skin as Velcro. Velcro has latches that intertwine and hold the two pieces together. Those latches are analogous to anchoring fibrils. Rafi does not have those latches, or anchoring fibrils and thus her two layers of skin are unable to bind together. Therefore, her skin blisters and tears with any friction or trauma. Just wearing underwear is enough friction to cause wounds on her.
She has dystrophic EB because of the lack of collagen 7. The lack of this protein, or complete absence of it, means Rafi can’t produce those anchoring filbrils so the epidermis cannot anchor to the dermis. She is considered recessive because both Jackie and I are carriers, something we did not know until she was born. In short, Rafi got two bad copies of the gene, thus resulting in a much more severe form.
Children with Rafi’s diagnosis unfortunately live a difficult life and even worse, her life expectancy isn’t long. 10% died before they were 10, 40% lose their battle before the age of 20 and 72% before 30.
Unfortunately, Rafi has the most severe subtype of Recessive Dystrophic EB, generalized severe, what they used to call Hallopeau-Siemens. From Jo-David Fine, MD, MPH from Vanderbilt University, an internationally known EB expert:
“The most severe subtype of generalized RDEB is referred to as the Hallopeau-Siemens variant. Cutaneous disease activity is present at birth. Patients characteristically develop milia, have absent or dystrophic nails, and develop extensive atrophic scarring. The oral cavity is severely involved with widespread erosions, blisters and soft tissue scarring. Microstamia, ankyloglossia, and caries are marked. Multifactorial anemia and growth retardation are both profound in these patients. A characteristic feature of RDEB-HS is the development of progressive acral contractures and partial or complete mitten deformities (pssudosyndactyly) of the hands and feet…….these musculoskeletal deformities may occur in the first few years of life, but more often occur with increasing age. Disfiguring scaring alopecia of the scalp may occur in some patients. The esophagus, small intestine, and anus may be severely involved, as can the urethra, bladder, vagina, and kidneys (the latter presenting as glomerulonephritis)…… Patients with RDEB-HS are at risk of death during early childhood as a result of overwhelming bacterial sepsis, secondary to widespread denudation of the skin. Patients with RDEB-HS are also at very high risk of developing and eventually dying from skin-derived squamous cell carcinomas during young to middle adulthood”.