Epidermolysis bullosa with congenital absence of skin: Clinical and genetic characterization of a 23-case series

Genetic Implications and Management of Epidermolysis Bullosa in the Saudi Arabian Population

Epidermolysis bullosa (EB) is a genetic skin disorder characterized by skin fragility and blister formation. This review explores the genetic basis and management of EB in the Saudi population, emphasizing the need for genetic insights to enable precise diagnosis, targeted treatments, and effective counseling. Diagnosis in Saudi Arabia relies on clinical assessments and genetic testing. Prenatal diagnosis may be suggested in families with children affected by EB, but it is not widely used in the Middle East. Current management focuses on symptom relief, while emerging experimental approaches such as gene and stem cell therapies are under extensive research. Challenges in EB research include developing effective targeted therapies and understanding the variability in how genotypes manifest phenotypically. Continuous research is crucial to enhance diagnostic methods, therapeutic approaches, and overall patient care.

Epidermolysis Bullosa: Two rare case reports of COL7A1 and EBS-GEN SEV KRT14 variants with review of literature

EPIDERMOLYSIS

Bullosa is a rare hereditary skin condition that causes blisters. Genes encoding structural proteins at or near the dermal-epidermal junction are mutated recessively or dominantly, and this is the primary cause of EB. Herein, two Chinese boys were diagnosed with the condition, each with a different variant in a gene that serves as a reference for EB genetic counseling. Skincare significantly impacted their prognosis and quality of life.

CASE PRESENTATION

Two Chinese boys, with phenotypically normal parents, have been diagnosed with distinct blister symptoms, one with Dominant Dystrophic Epidermolysis Bullosa and the other with a severe form of Epidermolysis Bullosa Simplex. The first patient had a G-to-A variant in the COL7A1 allele, at nucleotide position 6163 which was named "G2055A". The proband is heterozygous for Dystrophic Epidermolysis Bullosa due to a COL7A1 allele with a glycine substitution at the triple helix domain. A similar variant has been discovered in his mother, indicating its potential transmission to future generations. Another patient had severe Epidermolysis Bullosa Simplex with a rare c.377T > A  variant resulting in substitution of amino acid p.Leu126Arg (NM_000526.5 (c.377T > G, p.Leu126Arg) in the Keratin 14 gene. In prior literature, Keratin 14 has been associated with an excellent prognosis. However, our patient with this infrequent variant tragically died from sepsis at 21 days old. There has been a reported occurrence of the variant only once.

CONCLUSION

Our study reveals that Epidermolysis Bullosa patients with COL7A1 c.6163G > A and KRT14 c.377T>A variants have different clinical presentations, with dominant forms of Dystrophic EB having milder phenotypes than recessive ones. Thus, the better prognosis in the c.6163G > A patient. Furthermore, c.377T>A patient was more prone to infection than the patient with c.6163G>A gene variant. Genetic testing is crucial for identifying the specific variant responsible and improving treatment options.

Genetic analysis and prenatal diagnosis of recessive dystrophic epidermolysis bullosa caused by compound heterozygous variants of the COL7A1 gene in a Chinese family

BACKGROUND

Dystrophic epidermolysis bullosa (DEB) is an incurable and inherited skin disorder mainly caused by mutations in the gene encoding type VII collagen (COL7A1). The purpose of this study was to identify the causative genetic variants and further perform genetic diagnosis in a Chinese family affected by DEB.

METHODS

High-throughput sequencing was performed to analyze the genetic skin disorder-related genes of parents of the proband, and the variants were further confirmed in the other members by Sanger sequencing. Sanger sequencing, karyotype analysis, and chromosomal microarray analysis (CMA) were used together for prenatal diagnosis after the second pregnancy. The phenotype of the fetus was tracked after the diagnosis and induction of labor. Moreover, skin and muscle pathological examination and whole-exome sequencing (WES) of the skin and muscle tissue of the induced fetus were performed.

RESULTS

Here, we determined two heterozygous variants of the COL7A1 gene that contributed to the autosomal recessive DEB (RDEB) in the family, i.e., a novel pathogenic variant (c.8335G > T, p.E2779*) and a likely pathogenic variant (c.7957G > A, p.G2653R). Sanger sequencing of amniotic fluid cells showed that the fetus carried the above two compound heterozygous variants, and the karyotype analysis and CMA results showed no abnormality. The clinical phenotype and pathological results of the induced fetus were consistent with the characteristics of DEB. Further, WES analysis also confirmed a novel compound heterozygous variation in COL7A1, consisting of two variants, namely, c.8335G > T and c.7957G > A in the fetus.

CONCLUSION

This study expands the spectrum of disease-causing variants of COL7A1 and provides a theoretical basis for diagnosis, genetic counseling, and prognosis of families affected by RDEB.

Genotype-phenotype correlations on epidermolysis bullosa with congenital absence of skin: A comprehensive review

Congenital absence of skin (CAS) is a clinical sign associated with the main types of epidermolysis bullosa (EB). Very few studies have investigated the genetic background that may influence the occurrence of this condition. Our objective was to investigate genotype-phenotype correlations on EB with CAS through a literature revision on the pathogenic variants previously reported. A total of 171 cases (49 EB simplex, EBS; 23 junctional EB, JEB; and 99 dystrophic EB, DEB), associated with 132 pathogenic variants in eight genes, were included in the genotype-phenotype analysis. In EBS, CAS showed to be a recurrent clinical sign in EBS with pyloric atresia (PA) and EBS associated with kelch-like protein 24; CAS was also described in patients with keratins 5/14 alterations, particularly involving severe phenotypes. In JEB, this is a common clinical sign in JEB with PA associated with premature termination codon variants and/or amino acid substitutions located in the extracellular domain of integrin α6β4 genes. In DEB with CAS, missense variants occurring close to non-collagenous interruptions of the triple-helix domain of collagen VII appear to influence this condition. This study is the largest review of patients with EB and CAS and expands the spectrum of known variants on this phenomenon.