Transient bullous dermolysis of the newborn Q82.8

Hashimoto et al, 1985

Transient bullous dermolysis of the newborn is a rare form of dystrophic epidermolysis bullosa (DEB) associated with neonatal skin blistering. However, this usually improves markedly or even completely resolves during early life, with long-term persistent hyperpigmentation and also milia formation. Initially, nail dystrophies may also be detectable. After the skin blistering has stopped, the nails grow back normally. These also improve and usually grow back normally.

Transient bullous dermolysis of the newborn (TBDN) is caused by a heterozygous or compound heterozygous mutation in the COL7A1 gene (120120) on chromosome 3p21. To date, approximately 15 different mutations have been identified in the COL7A1 gene.

Autosomal dominant and autosomal recessive epidermolysis bullosa dystrophica (131750, 226600) are allelic diseases (= diseases caused by different mutations in one and the same gene).

Christiano et al (1997) identified a heterozygous mutation in the COL7A1 gene (120120,0039). Hammami-Hauasli et al. (1998) demonstrated compound heterozygosity for two mutations in the COL7A1 gene in a patient with TBDN (G2251E, 120120.0014; G1519D, 120120.0015). Heterozygous carriers of the G2251E allele had normal skin but isolated toe nail dystrophy (607523).

Shi BJ et al (2015) demonstrated case-related heterozygous substitution of guanine by adenine at nucleotide position 6136 of exon 73 in the triple helical domain of type VII collagen with replacement of glycine by serine at position p.G2046S . The mutation was classified as a pathogenic de novo mutation.

Hashimoto et al (1985) first described this condition in an African American child who developed large blisters on the extremities and other friction areas shortly after birth. The blisters healed rapidly, leaving hypopigmentation but no scars or milia. New blisters appeared within the first 4 months, but not thereafter. Later, the child developed completely normally. There was no significant family history.

In 1989, Hashimoto described about 2 more cases. In these cases of early childhood blistering, too, the blisters healed within 4 months without scarring. ES numerous lesional milia remained. No blisters or milia were seen at 17 months of age. In a Japanese girl, the blisters could be diagnosed as subepidermal. Fine et al (1990) described analogous casuistry.

McCollough et al (1991) reported a female infant with blisters on the hands, feet, trunk, face, and oral mucosa that healed without scarring. At 6 months of age, blisters occurred only occasionally. The mother suffered from analogous blistering.

Fassihi et al (2005) reported autosomal dominant TBDN in one proband, his father, and his paternal grandfather.

Evidence includes collagenolysis, reduction or loss of anchoring fibrils, and star-shaped inclusions in an expanded rough endoplasmic reticulum in the keratinocytes of the lower epidermis.

Skin biopsies show abnormal intraepidermal accumulation of type VII collagen, resulting in poorly constructed anchoring fibrils and a sublamina densa level of blistering (Fassihi et al. 2005).

Immunohistochemical studies revealed granular, perinuclear, intracytoplasmic deposits of COL7A1 in basal keratinocytes rather than exclusively linear deposits in the basement membrane (Fine et al. 1990).

In three families, blistering disappeared by 6 months of age; in the fourth family, blistering activity became minimal within the first two years of life, although some lesions continued to appear into the thirties. During blister formation, type VII collagen was retained in basal keratinocytes and not incorporated into the dermal-epidermal interface. However, after complete cessation or marked reduction in the extent of blistering, type VII collagen was expressed at normal intensity and in a linear distribution along the dermal-epidermal interface, as observed in normal human skin. Fine et al. (1991, 1993) concluded that the transient presence of mechanical fragility and blistering was due to a delay in the transport and integration of type VII collagen from basal keratinocytes into the basement membrane of the skin.