Epidermolysis Bullosa With Congenital Absence of Skin: Congenital Corneal Cloudiness and Esophagogastric Obstruction Including Extended Genotypic Spectrum of PLEC, LAMC2, ITGB4 and COL7A1

Epidermolysis bullosa (EB) is a rare and genetically heterogeneous disorder characterized by skin fragility and blister formation occurring spontaneously or after minor trauma. EB is accompanied by congenital absence of skin (EB with CAS) in some patients. Pathogenic variants of COL7A1 are responsible for EB with CAS in the vast majority of cases. Type and subtype diagnosis of EB with CAS generally requires specific immunohistological examinations that are not widely available plus targeted gene analysis. The present study aimed to determine the clinical features of five patients affected by EB with CAS and to identify the underlying genetic defects using whole exome sequencing (WES) followed by focused analysis of the target genes. Four patients had generalized skin involvement and one had localized defects. Two patients exhibited extremely severe skin manifestations and congenital cloudy cornea along with pyloric atresia, and one had partial esophagogastric obstruction and anuria due to vesicoureteric obstruction. In the WES analysis, the average coverage of the target exons was 99.05% (726 of 733 exons), with a range of 96.4–100% for individual genes. We identified four novel and two known pathogenic/likely pathogenic variants of five distinct genes in the examined families: PLEC:c.2536G > T (p.Glu846Ter); LAMC2:c.3385C > T (p.Arg1129Ter); KRT5:c.429G > A (p.Glu477Lys); ITGB4:c.794dupC (p.Ala266SerfsTer5); COL7A1:c.5440C > T (p.Arg1814Cys); and COL7A1:c.6103delG. All alleles were inherited from the parents, except for the KRT5 variant as a de novo finding. The findings reveal extremely rare phenotypes found in EB with CAS, namely congenital cloudy cornea, esophagogastric obstruction, and anuria, and extend the genotypic spectrum of EB-related genes. The data confirm that WES provides very high coverage of coding exons/genes and support its use as a reasonable alternative method for diagnosis of EB. The present data from an underrepresented population in Southeast Asia could further broaden the knowledge and research on EB.

Case Report: Uncommon Association of ITGB4 and KRT10 Gene Mutation in a Case of Epidermolysis Bullosa With Pyloric Atresia and Aplasia Cutis Congenita

Background: Epidermolysis bullosa is a rare form of genodermatosis produced by different gene mutations. The junctional form of the disease (JEB-PA) can associate pyloric atresia, renal abnormalities, and aplasia cutis congenita.

Case Description: A case of a male preterm newborn with suspicion of digestive tube malformation at fetal ultrasound and who was born by cesarian section. At birth, he presented extensive cutaneous aplasia on the lower limbs and bilaterally under ears; outer ear agenesis; nasal septum hypoplasia; micrognathia; multiple blisters on the face, trunk, and limbs; lower limb deformities and absence of toe nails. Pathological examination following a surgical procedure with unfavorable outcome showed pyloric atresia, junctional form of epidermolysis bullosa and aplasia cutis congenita. Homozygous variants in two genes were identified: c.3111+1G>A in ITGB4 (class 5) and c.1498G>T in KRT10 (class 3).

Conclusion: The particularity of our case is the novel finding of a coincidental occurrence in the context of consaguinity of two mutations in the ITGB4 and KRT10 genes, and clinical characteristics of epidermolysis bullosa.

A novel mutation in ITGB4 gene in a newborn with epidermolysis bullosa, pyloric atresia, and aplasia cutis congenita

Background

Epidermolysis bullosa with pyloric atresia (EB-PA), also known as Carmi syndrome, is an uncommon, autosomal recessive genodermatosis that typically affects the skin and gastrointestinal tract. EB-PA is caused by homozygous or compound heterozygous mutations in the integrin alpha 6 (ITGA6) gene on chromosome 2q31.1 or in the integrin beta 4 (ITGB4) gene on 17q25.1.

Case presentation

A male premature infant was born with aplasia cutis, atresia of the pylorus, and bilateral hydronephrosis. His clinical and imaging findings were compatible with EB-PA. A novel, small deletion of the last two bases in exon 6 and the first two nucleotides of intron 6 (c.565_566+2del) in ITGB4 gene was identified.

Conclusion

EB-PA-aplasia cutis congenita is known to be a non-treatable condition with a poor prognosis as the reported case. The novel mutation reported in this patient may lead to the lethal form of this disease. Identification of underlying genetic abnormality is critical to give genetic counseling.

Epidermolysis bullosa with congenital absence of skin: Review of the literature

BACKGROUND/OBJECTIVES

Bart syndrome was initially described as association of congenital absence of skin (CAS), nail abnormalities, and epidermolysis bullosa (EB). Further reports of patients with CAS and EB have been made with wide clinical heterogeneity among them. Current guidelines recommend the elimination of eponyms and use of the descriptive term EB with CAS.

METHODS

We performed a PubMed and Medline database search of patients with Bart syndrome or EB with CAS. We included case reports or case series that contained clinical and demographic information.

RESULTS

After review, 55 articles were included, reporting 96 patients. CAS involved the lower extremities in all patients, with additional upper limb, trunk, or head involvement in 17%. In all patients, the time to healing ranged from 2 weeks to 6 months; most received only conservative treatment. The subtype and frequency of associated EB most frequently reported were recessive dystrophic EB (41.4%) and dominant dystrophic EB (22.8%). Extracutaneous features were present in 29 patients; with pyloric atresia and ear malformations being the most common. The prognosis varied based on the subtype of EB and the presence of additional comorbidities; 50% of the patients with junctional EB with pyloric atresia and CAS died during the first months of life, while mortality among those with recessive dystrophic EB was 6.8%.

CONCLUSION

Epidermolysis bullosa with CAS is a clinically heterogeneous disorder, most often associated with recessive dystrophic EB, but other EB subtypes may occur. Further investigations are necessary to better establish a pathological mechanism for CAS, and its association with EB.

A Nonlethal Case of Junctional Epidermolysis Bullosa and Congenital Pyloric Atresia: Compound Heterozygosity in a Patient with a Novel Integrin Beta 4 Gene Mutation

We report a case of nonfatal junctional epidermolysis bullosa and pyloric atresia in a newborn. We identified a substitution (c.914C>T) for the integrin β4 gene that has been associated with favorable outcome. A novel mutation (c.2011T>G) of unknown significance was also found in this patient who is now thriving.

Epidermolysis Bullosa with Pyloric Atresia and Aplasia Cutis in a Newborn Due to Homozygous Mutation in ITGB4

BACKGROUND

Epidermolysis bullosa with pyloric atresia (EB-PA) is an autosomal recessive disorder due to mutations in ITGA6 and/or ITGB4, resulting in altered expression of α6β4 integrin. EB-PA can also occur with aplasia cutis.

CASE REPORT

We present a newborn with EB-PA and aplasia cutis, born of consanguineous parents, with a homozygous c.3793+1G>A mutation affecting ITGB4, previously described only in the heterozygous state with other mutations.

CONCLUSION

The previously unreported homozygous c.3793+1G>A mutation affecting ITGB4 causes a severe form of junctional epidermolysis bullosa with pyloric atresia and aplasia cutis.

Epidermolysis bullosa simplex in sibling Eurasier dogs is caused by a PLEC non-sense variant

BACKGROUND

Plectin, a large linker protein found in many tissues, acts to connect components of the cytoskeleton to each other. In the epidermis, plectin binds keratin intermediate filaments to hemidesmosomes. A deficiency of plectin in the skin leads to blister formation in the basal layer and the disease epidermolysis bullosa simplex (EBS).

HYPOTHESIS/OBJECTIVES

To describe a novel blistering disease that arose spontaneously in a litter of puppies.

ANIMALS

Two female and one male 20-day-old Eurasier puppies, from a litter of six, were presented for evaluation of failure to thrive and then euthanized due to poor prognosis. The puppies had ulcers on the lips, tongue, nasal planum, paw pads and abdomen.

RESULTS

Immunolabelling on frozen skin for basement membrane proteins revealed patchy and weak to absent staining for plectin as compared with strong linear staining in normal dogs. Ultrastructurally, hemidesmosomes were irregularly shaped and had loss of distinction between inner and outer plaques. Pedigree analysis supported an autosomal recessive mode of inheritance. A premature stop codon was discovered in exon 27 of PLEC that resulted in the production of a severely truncated protein.

CONCLUSION

The study describes the first documented spontaneous EBS associated with a PLEC variant in domestic animals.

Generalized severe junctional epidermolysis bullosa with congenital absence of skin in churra lambs

BACKGROUND

Up to 0.5% of churra lambs from two genetically related flocks showed congenital skin lesions of variable severity, jeopardizing the life of the lambs in the most severe cases.

HYPOTHESIS/OBJECTIVES

The primary objective of this study was to classify the type of congenital epithelial disease suffered by these animals, based on the description of the macroscopic skin defects, the histological and ultrastructural changes and the hereditary nature of the condition.

ANIMALS

Thirty affected newborn lambs from two genetically related flocks were studied. Three additional lambs acquired from two other flocks, which had no grossly apparent skin lesions and had died of infectious diseases, were studied as unaffected control animals.

METHODS

Histological and ultrastructural examinations of skin and oral mucosa samples were performed. Pedigree analyses were used to investigate genealogical relationships.

RESULTS

Generalized severe junctional epidermolysis bullosa with congenital absence of skin was described in all lambs studied and an autosomal recessive mode of inheritance was identified.

CONCLUSIONS AND CLINICAL IMPORTANCE

The pathological findings and mode of inheritance in these lambs are similar to an inherited epidermolysis bullosa subtype of humans, which has not been reported previously in veterinary medicine.

Plectin-related skin diseases

Plectin has been characterized as a linker protein that is expressed in many cell types and is distinctive in various isoforms in the N-terminus and around the rod domain due to complicated alternative splicing of PLEC, the gene encoding plectin. Plectin deficiency causes autosomal recessive epidermolysis bullosa simplex (EBS) with involvement of the skin and other organs, such as muscle and gastrointestinal tract, depending on the expression pattern of the defective protein. In addition, a point mutation in the rod domain of plectin leads to autosomal dominant EBS, called as EBS-Ogna. Plectin can be targeted by circulating autoantibodies in subepidermal autoimmune blistering diseases. This review summarizes plectin-related skin diseases, from congenital to autoimmune disorders.

Pyloric atresia

We present a case of a female newborn with a single air bubble on abdominal x-ray by pyloric atresia and a short review of the literature.

Epidermolysis bullosa with pyloric atresia

Epidermolysis bullosa (EB) with pyloric atresia (PA) is a rare form of EB. This article describes the clinical and pathologic features and molecular genetics of EB-PA, the mutations in the alpha(6)beta(4) integrin and plectin genes that cause EB-PA, and the clinical implications of molecular genetics on EB-PA.

Life-threatening cutaneous conditions in neonates

One of the major medical concerns in neonates is their vulnerability to life-threatening complications. Early diagnosis of potentially serious medical conditions is essential in prevention of such complication by prompt administration of appropriate treatments. Recognition of cutaneous manifestations of potentially fatal diseases may assist a clinician in management of newborns. To overview the full spectrum of this category of conditions, Medline search was performed for cases of cutaneous manifestations associated with mortality during the first month of live that were published in the English language literature since 1977. This is a concise review of the clinical aspects of most of the potentially life-threatening disorders in neonates divided by basic morphology of their cutaneous manifestations.

Molecular basis of autosomal recessive diseases among the Palestinian Arabs

In the review of the literature, 71 different autosomal recessive diseases have been delineated that are relatively frequent among Palestinian Arabs. Among those, in 40 the mutation(s) responsible for the diseases are known. Fourteen of these disorders were caused by a single mutation, while the other 26 were due to multiple mutations. Most of the mutations were found in homozygosity among the affected patients. It is probable that the high frequency of most of the genetic diseases among the Palestinian Arabs is due to a founder effect as the result of the high consanguinity rates in this population. However, in some cases the high frequency was demonstrated to be secondary to the presence of multiple mutations, either allelic or in different genes in a small geographic region. This phenomenon remains unexplained but may be secondary to a selective advantage to the carriers, either specific to the region or to the population.

Epidermolysis bullosa with congenital pyloric atresia: novel mutations in the beta 4 integrin gene (ITGB4) and genotype/phenotype correlations

Epidermolysis bullosa with pyloric atresia (EB-PA: OMIM 226730), also known as Carmi syndrome, is a rare autosomal recessive genodermatosis that manifests with neonatal mucocutaneous fragility associated with congenital pyloric atresia. The disease is frequently lethal within the first year, but nonlethal cases have been reported. Mutations in the genes encoding subunit polypeptides of the alpha 6 beta 4 integrin (ITGA6 and ITGB4) have been demonstrated in EB-PA patients. To extend the repertoire of mutations and to identify genotype-phenotype correlations, we examined seven new EB-PA families, four with lethal and three with nonlethal disease variants. DNA from patients was screened for mutations using heteroduplex analysis followed by nucleotide sequencing of PCR products spanning all beta 4 integrin-coding sequences. Mutation analysis disclosed 12 distinct mutations, 11 of them novel. Four mutations predicted a premature termination codon as a result of nonsense mutations or small out-of-frame insertions or deletions, whereas seven were missense mutations. This brings the total number of distinct ITGB4 mutations to 33. The mutation database indicates that premature termination codons are associated predominantly with the lethal EB-PA variants, whereas missense mutations are more prevalent in nonlethal forms. However, the consequences of the missense mutations are position dependent, and substitutions of highly conserved amino acids may have lethal consequences. In general, indirect immunofluorescence studies of affected skin revealed negative staining for beta 4 integrin in lethal cases and positive, but attenuated, staining in nonlethal cases and correlated with clinical phenotype. The data on specific mutations in EB-PA patients allows prenatal testing and preimplantation genetic diagnosis in families at risk.

Duodenal atresia, biliary atresia, and intestinal infarct in truncal aplasia cutis congenita

A newborn boy with aplasia cutis congenita had biliary atresia, distal duodenal atresia, and a severe infarct of the intestine resulting in complete absence of the entire midgut. The boy died due to biliary atresia and severe short gut syndrome approximately 3 weeks after birth. While the association of duodenal atresia with aplasia cutis congenita has been described, the findings of biliary atresia and midgut atresia in association with aplasia cutis congenita have not been described previously.