The Position of Targeted Next-generation Sequencing in Epidermolysis Bullosa Diagnosis

Abstract

The precise classification of epidermolysis bullosa (EB) into 4 main types and more than 30 subtypes is based on the level of skin cleavage, as well as clinical and molecular features, and is crucial for early prognostication, case management, genetic counselling and prenatal or pre-implantation diagnosis. We report here the molecular pathology of 40 consecutive cases of suspected EB, which were investigated by immunofluorescence mapping (IFM) and/or by a targeted next-generation sequencing (NGS) multi-gene panel. IFM correctly established the EB subtype in 76% of cases, while the molecular pathology was completely elucidated in 90% of cases by the targeted NGS multi-gene panel. Thirteen previously unreported mutations in EB genes were identified. In cases with unclear clinical and IFM findings, mutations were found by NGS in previously unexpected genes. IFM was useful in delivering fast results in newborns, and in indicating the consequences of the variants of uncertain significance on protein level. This study underscores the efficacy of the strategy of combining targeted NGS with IFM in resolving unusual EB phenotypes. It also suggests that, despite technological advances, careful clinical evaluation and deep phenotyping remains a crucial factor that dictates successful diagnosis of EB.

An overview of the genetic basis of epidermolysis bullosa in Brazil: discovery of novel and recurrent disease‐causing variants

“…Vahidnezhad et al developed a multigene panel including 21 genes and found an efficiency of 83.5% predicting the subtype of EB in 76 out of 91 families . Has et al elucidated 90% (36 of 40) of the studied cases by a NGS‐panel that included 49 genes . Finally, Lucky et al found an efficiency of 97.7% (42/43 patients) in an NGS assay that included 21 genes, in which all the identified mutations were present in only five genes ( KRT5 , KRT14 , LAMB3 , COL17A1 , COL7A1 ) .…”

Inherited epidermolysis bullosa: New diagnostics and new clinical phenotypes

“…Using an EB multigene panel, we have recently identified an additional unrelated patient. He had mild skin fragility and was a compound heterozygote for c.46C>T and a mutation leading to a premature termination codon …”

“…For research purposes, other candidate genes can be added if they are functionally related or suspected to be potential functional modifiers. Based on our recent experience, we have designed a panel containing 20 EB‐associated genes and 29 supplementary candidate genes. With this approach, we achieved a 90% detection rate for the disease‐causing variants.…”

“…For research purposes, other candidate genes can be added if they are functionally related or suspected to be potential functional modifiers. Based on our recent experience, [6] we have designed a panel containing 20…”

“…He had mild skin fragility and was a compound heterozygote for c.46C>T and a mutation leading to a premature termination codon. [6]…”