Prenatal exclusion of pyloric atresia-junctional epidermolysis bullosa syndrome

Clinical outcomes and molecular profile of patients with Carmi syndrome: A systematic review and evidence quality assessment

PURPOSE

Carmi syndrome is a rare genetic disorder characterized by junctional epidermolysis bullosa (JEB) and pyloric atresia (PA). We reviewed the clinicopathologic and molecular features of patients with Carmi syndrome to identify predictors of clinical outcome and guide surgical PA repair.

METHODS

A PRISMA-compliant systematic literature review of PubMed, CINAHL, and the Cochrane Library was performed.

RESULTS

63 original studies including a total of 100 patients were included. PA type 1 and 2 were equally prevalent (47.2%, 95% CI: 34.4-60.3). Heineke-Mikulicz pyloroplasty (96%, 95% CI: 78.8-99) and gastroduodenostomy (72%, 95% CI: 52.2-85.9) were the most common type 1 and 2 PA repairs, respectively. Seventy lethal cases were identified (74.5%, 95% CI: 64.8-83.5). Of the 73 patients that received an operation, 49 died (67.1%, 95% CI: 55.7-76.8) and 24 survived (32.9%, 95% CI: 23.2-44.3). Integrin α6β4 expression was absent or markedly reduced in lethal cases. Integrin α6, plectin-1, cephalic integrin β4 (exon 3 to intron 11), and premature termination codon mutations were also associated with poor prognosis.

CONCLUSIONS

Although Carmi syndrome typically has poor prognosis, 1 in 4 patients exhibits nonlethal phenotypes. Immunofluorescence mapping and genetic consultation can guide surgical intervention and provide valuable family planning information.

EVIDENCE RATING/CLASSIFICATION

Prognosis study, Level IV.

Pyloric atresia associated with epidermolysis bullosa--three cases presenting in three months

Three neonates presenting with pyloric atresia and epidermolysis bullosa are described in this report. Two babies underwent surgery for pyloric atresia, and 1 of these has survived until 3 months of age with no complications. The clinical presentation and complications of the pyloric atresia-epidermolysis bullosa syndrome are discussed with a brief review of literature.

Junctional epidermolysis bullosa with pyloric stenosis presenting with electron microscopic findings suggestive of epidermolysis bullosa simplex

We present an infant girl who was born with pyloric stenosis and epidermolysis bullosa (EB). Electron microscopy of a skin biopsy specimen showed findings suggestive of EB simplex, but immunofluorescence (IF) mapping of the same specimen established the diagnosis of junctional EB. Because electron microscopy findings may sometimes be misleading, an EB patient with pyloric stenosis and electron microscopy findings suggestive of EB simplex should have a biopsy specimen examined by immunofluorescence mapping, which may confirm that the patient in fact has junctional EB.

Epidermolysis bullosa simplex associated with muscular dystrophy: phenotype-genotype correlations and review of the literature

BACKGROUND

Epidermolysis bullosa simplex associated with muscular dystrophy (EBS-MD; OMIM# 226670) is an autosomal recessive disorder caused by genetic defects in the plectin gene. Because EBS-MD is relatively rare, and gene defects have been elucidated only in a limited number of patients, the precise phenotype-genotype correlations have not yet been fully elucidated.

OBJECTIVE

The purpose of this study was to define clinical features of EBS-MD and to clarify its phenotype-genotype correlations.

METHODS

Clinical, ultrastructural, immunohistochemical, and molecular features of 4 unrelated Japanese patients with EBS-MD were recorded. In addition, 6 cases with defined plectin gene mutations reported in the literature were reviewed.

RESULTS

In skin of the EBS-MD patients, the blister formation always occurs just above the hemidesmosomes, and expression of plectin is absent or markedly reduced in all cases examined. All 10 patients, including 6 cases in the literature, showed generalized blistering at birth or soon thereafter, and experienced nail deformities. In addition, decayed teeth (5 cases), urethral strictures (3), mild palmoplantar hyperkeratosis (2), infantile respiratory complications (2), alopecia (1), and laryngeal webs (1) were present. All 8 patients who were older than 9 years demonstrated considerable muscle weakness, and the majority of them ended up being wheelchair bound. Among the 10 patients, 7 were products of consanguineous marriage, 9 have premature termination codon (PTC) mutations in both alleles of the plectin gene, and 7 cases were homozygous for the mutation. One patient who is homozygous for a 2719del9 in-frame deletion mutation that resulted in elimination of 3 amino acids, QEA, could still walk at the age of 46 and showed milder clinical severity.

CONCLUSION

EBS-MD reveals clinical features not only characteristic of EBS and MD, but also other manifestations including urethral, dental, and respiratory complications. The majority of patients are products of consanguineous marriage and have homozygous plectin gene mutations. Whereas patients with PTC mutations in both alleles typically showed severe clinical features of EBS-MD and ended up being wheelchair bound, a homozygous patient for an in-frame deletion mutation showed positive, yet attenuated, plectin expression and milder clinical phenotype. Thus plectin immunofluorescence, combined with identification of the underlying plectin mutations, is of value in predicting the severity of the muscle involvement that occurs later in life of patients with EBS-MD.

Immunohistopathologic diagnosis of epidermolysis bullosa

Routine histologic study usually is insufficient to subclassify epidermolysis bullosa (EB); currently, electron microscopic evaluation has been the gold standard. A major advance recently has been made in elucidating the molecular basis of several major forms of EB. Concomitantly, immunoreagents have been developed to map antigens in the basement membrane zone. Some of these reagents facilitate the classification of EB into types and subtypes and can be used as an adjunct informative screening procedure to direct mutation identification efforts using DNA technologies. The current review provides an overview of these recent developments and a more detailed account of the immunohistopathologic diagnosis of EB.

Prenatal diagnosis as a test for genodermatoses: its past, present and future

The prenatal diagnosis (PND) of severe hereditary skin diseases started in the early 1980s using fetal skin biopsy techniques based on ultrastructural and immunohistochemical abnormalities of the fetal skin. Recent success in identifying responsible genes and demonstrating mutations in such genes has set the stage for DNA-based PND in the 1990s. Common examples of skin conditions which can be prenatally diagnosed include epidermolysis bullosa, oculocutaneous albinism and Harlequin ichthyosis in which the severity of the clinical phenotype appears to justify PND in families at risk. More recently, preimplantation diagnoses of inherited diseases have become possible using in vitro fertilization techniques. The diagnosis consists of a blastomere biopsy of the six to ten-cell embryo and a DNA analysis of single blastomeres. Disease-free embryos are selected for transfer to the uterus, thereby avoiding the need for termination of a fetus found to be affected by conventional PND. Furthermore, carrying out a PND using a single fetal cell from the maternal blood, such as nucleated erythrocytes, has become technically feasible. Although there are many questions that remain unanswered, the outlook for further development of noninvasive PND in the future appears optimistic.

Novel mutations in the LAMB3 gene shared by two Japanese unrelated families with Herlitz junctional epidermolysis bullosa, and their application for prenatal testing

The LAMB3 gene encoding the beta3 chain of laminin 5 is a candidate gene for mutations in the autosomal recessive blistering skin disorder, junctional epidermolysis bullosa. In this study, we performed genetic analyses in two unrelated Japanese families with Herlitz junctional epidermolysis bullosa and identified two novel nonsense mutations in the LAMB3 gene. One of them, Q166X (CAG --> TAG), was found in the maternal allele of family 1 and the paternal allele of family 2. Conversely, the other mutation, W610X (TGG --> TGA), was found in the paternal allele of family 1 and the maternal allele of family 2. Thus, probands of both families were compound heterozygotes for these nonsense mutations. Haplotype analyses with intragenic LAMB3 polymorphisms suggested that both mutations had arisen independently in these two families. Both mutations create a premature translation termination codon predicting truncated beta3 chains that lead to absent expression of laminin 5 in the epidermal basement membrane zone. Based on these results, DNA-based prenatal diagnosis was performed by chorionic villus sampling for subsequent pregnancies in both families. Both fetuses were found to be heterozygous carriers of the W610X mutation together with a normal LAMB3 allele, indicating that they were phenotypically unaffected. These findings expand the repertoire of LAMB3 mutations in junctional epidermolysis bullosa, and emphasize the notion that premature termination codons in both alleles of the laminin 5 genes result in Herlitz junctional epidermolysis bullosa.

Novel ITGB4 mutations in a patient with junctional epidermolysis bullosa-pyloric atresia syndrome and altered basement membrane zone immunofluorescence for the alpha6beta4 integrin

Immunofluorescence studies of junctional epidermolysis bullosa with pyloric atresia (JEB-PA) have suggested abnormalities in the expression of the alpha6 beta4 integrin, an integral component of hemidesmosomes. In this study, we examined a family with two affected individuals with JEB-PA for mutations in the ITGA6 and ITGB4 genes which encode the alpha6 and beta4 integrin polypeptides, respectively. Mutation detection strategy based on PCR amplification of genomic DNA, followed by heteroduplex analysis and direct nucleotide sequencing, did not reveal sequence variants in ITGA6. Putative pathogenic mutations, however, were identified in both ITGB4 alleles. Specifically, the proband was a compound heterozygote for a 1-bp maternal deletion, 3434delT, and an 8-bp paternal deletion, 4050de18. Both mutations result in a frameshift and premature termination codon downstream from the deletion. At the protein level, immunofluorescence of the skin of the proband revealed negative staining for the integrin alpha6 and markedly reduced staining for the beta4 subunit. Thus, the results support the notion of close association of the alpha6 beta4 integrin subunits and further attest to the critical role of this integrin in providing physiologic stability to the dermal-epidermal junction.

Gastric outlet obstruction and epidermolysis bullosa

We describe a case of pyloric atresia coexisting with epidermolysis bullosa, almost certainly of the junctional type. The coexistence of pyloric atresia and junctional epidermolysis bullosa (PA-JEB syndrome) has been repeatedly observed. This syndrome has several clinical features that distinguish it from Herlitz junctional epidermolysis bullosa (JEB). These include a lack of prominent granulation tissue formation and increased frequencies of genitourinary tract involvement and ear anomalies. Aplasia cutis congenita is sometimes present; esophageal atresia is uncommonly present. In all 12 patients examined to date, normal basement membrane zone expression of laminin-5 biochemically distinguishes PA-JEB syndrome from Herlitz JEB. Mutations in the beta 4 integrin gene have been observed in one patient with PA-JEB syndrome. Thus there are both clinical and biochemical reasons to separate the PA-JEB syndrome from Herlitz JEB. This is the second known case of papillary hyperplasia of the amnion to be seen in any setting. The other was a case of JEB without pyloric atresia.

A novel keratin K5 gene mutation in Dowling-Meara epidermolysis bullosa simplex

We examined keratin K14 and K5 genes mutation in a Japanese Dowling-Meara epidermolysis bullosa simplex patient with severe generalized blistering and erosions at birth. The patient had a C to T transition at the first position of codon 174 in the keratin K5 gene, which resulted in a Leu->Phe substitution at the highly conserved 1A domain in keratin K5. Thus, our results revealed a novel mutation in the helix initiation peptide of keratin K5.

Molecular basis of recessive dystrophic epidermolysis bullosa: genotype/phenotype correlation in a case of moderate clinical severity

Mutations within the gene encoding the anchoring fibril protein type VII collagen (COL7A1) have recently been established as the pathogenetic basis for the inherited blistering skin disorder, dystrophic epidermolysis bullosa. We report a patient with a moderately severe phenotype of recessive dystrophic epidermolysis bullosa. We report a patient with a moderately severe phenotype of recessive dystrophic epidermolysis bullosa, in whom COL7A1 mutations have been identified on both alleles. The patient is a 5-y-old Japanese male of nonconsanguineous parents, with clinical features including generalized trauma-induced blistering since birth, complete loss of nails, and partial fusion of the fingers and toes. Immunofluorescence microscopy examination of the dermal-epidermal junction in the patient's skin revealed near-normal intensity staining with an antitype VII collagen antibody (LH7:2). Transmission electron microscopy showed a reduced number of thin, poorly-formed anchoring fibrils. PCR amplification of genomic DNA, followed by heteroduplex analysis, and nucleotide sequencing demonstrated that the patient was a compound heterozygote for a nonsense mutation (E2858X) within the NC-2 domain of type VII collagen and a missense mutation (G2576R) within the type VII collagen triple helix. Both mutations were verified by restriction endonuclease digestion. Information about these mutations advances our understanding of genotype-phenotype correlations in dystrophic epidermolysis bullosa, and further delineates the mechanisms involved in dermal-epidermal dysadhesion.