Other EB Simplex Subtypes

Autosomal recessive EBS is a rare form of EB simplex due to mutations in keratin 14. It presents at birth with generalized blistering; blistering around the anus and genitalia may occur. Milia and scarring may be observed, and dystrophic nails are common. Keratoderma may be seen. Although dental enamel is normal, affected children appear to have a slightly increased tendency to dental caries. Blistering of the mouth is common. Affected children typically do not have poor growth, anemia, or problems with the trachea/respiratory tract, intestines/gastrointestinal tract, eyes or genitourinary tract with the exception of chronic constipation. There is no increased risk of skin cancer.

EBS with mottled pigmentation is a rare autosomal dominant form of EB simplex caused by mutations in keratin 5. It presents at birth with widespread blistering. Milia and scarring typically do not occur, although a mild form of keratoderma may occur. Nail dystrophy usually is mild. The characteristic feature of the disease is the development of a brown skin discoloration after recurrent blistering on the body and extremities. Dental enamel is normal, and there does not appear to be an increased tendency to dental caries. Blistering of the mouth does not occur, and affected children typically do not develop poor growth, anemia, or problems with the trachea/respiratory tract, intestines/gastrointestinal tract, eyes or genitourinary tract. There is no increased risk of skin cancer.

EBS-migratory circinate is another rare autosomal dominant form of EB simplex caused by a mutation in the keratin 5 gene. Widespread blistering occurs at birth. The characteristic feature is the development of patches of erythema (redness) that appear to “migrate” on the skin, leaving behind hyperpigmentation or brown discoloration of the skin. Milia and scarring typically do not occur. Dental enamel is normal, and there does not appear to be an increased tendency to dental caries. Blistering of the mouth does not occur, and affected children typically do not develop poor growth, anemia, or problems with the trachea/respiratory tract, intestines/gastrointestinal tract, eyes or genitourinary tract. There is no increased risk of skin cancer.

EBS-Ogna is a rare autosomal dominant form of EB simplex caused by a mutation in the plectin gene. It is characterized by blistering at birth that predominantly involves the hands and feet, although more generalized blistering also may develop. Milia and scarring typically do not occur. The characteristic features of the disease is the development of very thickened nails, termed onychogryphosis, as well as a tendency to bruise. Dental enamel is normal, and there does not appear to be an increased tendency to dental caries. Blistering of the mouth does not occur, and affected children typically do not develop poor growth, anemia, or problems with the trachea/respiratory tract, intestines/gastrointestinal tract, eyes or genitourinary tract. There is no increased risk of skin cancer.

Lethal acantholytic EBS is an extremely rare form of autosomal recessive EB simplex that is caused by mutations in the desmoplakin gene. Only two affected newborns have been described, both of whom died soon after birth. In the affected newborns, generalized erosions and oozing at birth such that the skin appears to “peel off” without true blister formation was reported. Milia and scarring were not observed, although significant nail dystrophy was seen. Alopecia of the scalp (hair loss or poor growth) and the presence of teeth at birth (neonatal teeth) were reported. Blistering of the mouth and intestines/gastrointestinal tract, genitourinary tract and trachea/respiratory tract was noted. Eye involvement was not reported.

Plakophilin deficiency, also known as ectodermal dysplasia-skin fragility syndrome, is another very rare autosomal recessive form of EB simplex caused by plakophilin mutations. Generalized erosions with rare blisters are present at birth. Milia and scarring are not seen. Nail dystrophy is common, as is sparse hair. Keratoderma with fissuring of the palms and soles, fissuring of the tongue and characteristic fissuring around the mouth are characteristic. Dental enamel is normal, and there does not appear to be an increased tendency to dental caries. Poor growth, constipation, esophageal stricture, sparse eyelashes and inflammation of the eyelids (blepharitis) have been reported. Involvement of the trachea/respiratory tract and genitourinary tract have not been reported.