Challenges of the differential diagnosis between the subtypes of the junctional epidermolysis bullosa: presentation of two clinical cases

Background: Epidermolysis bullosa (EB) is a rare hereditary skin disease. It is subdivided into EB simplex (EBS), junctional EB (JEB), dystrophic EB (DEB) and Kindler syndrome. JEB is diagnosed in 2 per 1,000,000 of the population. There are few descriptions of clinical JEB cases in the literature. Clinical diagnosis of JEB and its subtypes is a challenge, especially in the early age. The paper presents 2 clinical cases of JEB in patients of the West Slavonic origin. Clinical case No. 1 was a girl of Ukrainian ethnicity, with confirmed definitive diagnosis of severe generalized JEB. Molecular genetic tests identified mutations of the LAMA3 gene that had not been described previously. The patient died at the age of 24 months from acute respiratory failure. When the patient was alive, her EB type and subtype was not possible to identify, because she had a combination of clinical manifestations typical for various JEB subtypes. Despite such symptoms as hoarse voice, stenoses, granulation tissue of typical location, laryngeal granulations, the girl was steadily gaining weight, with some periods of relative stabilization of the skin disease; she also had longer life longevity than was common for patients with severe generalized JEB. All this made a precise diagnosis difficult. Clinical case No. 2: an ethnic Russian boy with non-classified JEB. Molecular genetic testing helped to identify a homozygote mutation in the LAMA3 gene that had not been previously described; reliable determination of the subtype was not possible. The patient had mixed clinical manifestation similar both to generalized severe JEB and to laryngo-onycho-cutaneous (LOC) syndrome. During his lifetime, the patient was clinically diagnosed with Hallopeau acrodermatitis and LOC syndrome. The differential diagnostic problems were associated with the presence of signs not typical for each of the subtypes. Significant life longevity of the proband is not characteristic for severe generalized JEB (at the time of the publication the patient is 13 years old), whereas for LOC syndrome the absence of eye involvement is not typical, as well as severe laryngeal involvement at adolescence.

Conclusion: Detailed descriptions of phenotype of JEB subtypes including rare and minimal clinical signs can be useful to study the clinical manifestations and natural course of the disease, including its differential diagnosis.