A Case of Junctional Epidermolysis Bullosa with Pyloric Atresia Due to Integrin β4 Gene Mutations

Nagisa Yoshihara, Hajime Nakano, Daisuke Sawamura, Asami Kamata, Hiroyuki Matsuzaki, Takashi Etoh and Shigaku Ikeda*

A Case of Junctional Epidermolysis Bullosa with Pyloric Atresia Due to Integrin β4 Gene Mutations.

Epidermolysis bullosa is a rare hereditary disorder characterized by mucocutaneous
fragility and is caused by mutations in the genes that encode structural proteins in
the epidermal basement membrane.

Even a slight external force can cause separation of the epidermis from the dermis,
leading to the formation of blisters and erosions on the skin and mucosa.

Epidermolysis bullosa is largely classified into simplex, junctional and dystrophic
types according to the site of cleft formation.

There is also a subtype associated with pyloric atresia called epidermolysis bullosa
with pyloric atresia, which is divided into epidermolysis bullosa simplex with pyloric
atresia and junctional epidermolysis bullosa with pyloric atresia.

JEB-PA is caused by abnormalities in the ITGA6 or ITGB4 gene. The ITGA6 and ITGB4 genes
encode integrin α6 and integrin β4, respectively.

JEB-PA involves both lethal and non-lethal mutations. Lethal JEB-PA is generally
caused by premature stop codons in both alleles, while nonlethal JEB-PA is mainly
caused by a missense or splicing mutation in at least one allele. The c.600dupC mutation
observed in the present case generates a PTC and has also been previously reported in one case
by Masunaga et al.

Masunaga et al reported that an amino acid substitution from glutamine to proline at position
425 reduced the α-helix formation ability of integrin β4 in the adjacent region and that the gene
abnormality Q425P was the pathogenic factor in that case.

In the present case, both positions of the predicted amino acid substitution are close
to the N-terminus of ITGB4. These positions also may influence the clinical severity.

Dermatol Open J. 2019; 4(1): 7-9. doi: 10.17140/DRMTOJ-4-134