Isolated deficient alpha6beta4 integrin expression in the gut associated with intractable diarrhea

Type II Congenital Pyloric Atresia with Desquamative Enteropathy Diagnosed Postoperatively: A Case Report

Congenital pyloric atresia (CPA) is a rare condition that presents as gastric outlet obstruction in the first few weeks of life. Isolated CPA typically carries a good prognosis but when associated with other conditions such as multiple intestinal atresia or epidermolysis bullosa (EB), the outcomes are generally poor. This report describes a four-day-old infant who presented with nonbilious emesis and weight loss in whom an upper gastrointestinal contrast study revealed gastric outlet obstruction determined to be consistent with pyloric atresia. The patient underwent operative repair via Heineke-Mikulicz pyloroplasty. Postoperatively, the patient continued to have severe diarrhea and was found to have desquamative enteropathy though had no skin findings consistent with EB. This report emphasizes consideration of CPA as a differential diagnosis for neonates presenting with nonbilious emesis and demonstrates the association between CPA and desquamative enteropathy without EB.

Epidermolysis bullosa with pyloric atresia associated with compound heterozygous ITGB4 pathogenic variants: Minimal skin involvement but severe mucocutaneous disease

We report a case of junctional epidermolysis bullosa with pyloric atresia (JEB-PA) with minimal skin involvement but severe protein-losing enteropathy and airway involvement. Genetic analysis revealed heterozygous mutations in the ITGB4 gene encoding integrin β4 protein. Parental testing confirmed inheritance of frameshift variant (c.794dupC) as maternal and splice site variant (c.1608C>T/p.Cys536Cys) as paternal. Immunofluorescence mapping of her skin revealed a subepidermal blister with decreased and frayed integrin β4 at both the floor and the roof of the blister, while the intestinal mucosa showed complete absence of integrin β4. We review the literature and discuss the differential expression of integrins in the skin and gastrointestinal tract, as well as the role of chronic inflammation in the pathogenesis of EB.

Hemidesmosome integrity protects the colon against colitis and colorectal cancer

OBJECTIVE

Epidemiological and clinical data indicate that patients suffering from IBD with long-standing colitis display a higher risk to develop colorectal high-grade dysplasia. Whereas carcinoma invasion and metastasis rely on basement membrane (BM) disruption, experimental evidence is lacking regarding the potential contribution of epithelial cell/BM anchorage on inflammation onset and subsequent neoplastic transformation of inflammatory lesions. Herein, we analyse the role of the α6β4 integrin receptor found in hemidesmosomes that attach intestinal epithelial cells (IECs) to the laminin-containing BM.

DESIGN

We developed new mouse models inducing IEC-specific ablation of α6 integrin either during development (α6^ΔIEC) or in adults (α6^ΔIEC-TAM).

RESULTS

Strikingly, all α6^ΔIEC mutant mice spontaneously developed long-standing colitis, which degenerated overtime into infiltrating adenocarcinoma. The sequence of events leading to disease onset entails hemidesmosome disruption, BM detachment, IL-18 overproduction by IECs, hyperplasia and enhanced intestinal permeability. Likewise, IEC-specific ablation of α6 integrin induced in adult mice (α6^ΔIEC-TAM) resulted in fully penetrant colitis and tumour progression. Whereas broad-spectrum antibiotic treatment lowered tissue pathology and IL-1β secretion from infiltrating myeloid cells, it failed to reduce Th1 and Th17 response. Interestingly, while the initial intestinal inflammation occurred independently of the adaptive immune system, tumourigenesis required B and T lymphocyte activation.

CONCLUSIONS

We provide for the first time evidence that loss of IECs/BM interactions triggered by hemidesmosome disruption initiates the development of inflammatory lesions that progress into high-grade dysplasia and carcinoma. Colorectal neoplasia in our mouse models resemble that seen in patients with IBD, making them highly attractive for discovering more efficient therapies.

Intractable diarrhea with tufting enteropathy: a favorable outcome is possible

BACKGROUND AND OBJECTIVE

Tufting enteropathy (TE) is a congenital abnormality of intestinal mucosa development characterized by severe intestinal failure requiring parenteral nutrition (PN) and, in some cases, small bowel transplantation. A few patients have had a more favorable outcome. The objective of this study was to evaluate possible correlations between histological lesion severity in duodenal biopsies and clinical outcomes in children with TE.

PATIENTS AND METHODS

We retrospectively reviewed the records of patients diagnosed with TE between 1993 and 2003 at our institution based on intractable neonatal-onset diarrhea with prolonged dependence on PN and duodenal biopsy findings of villous atrophy, epithelial dysplasia with enterocyte dedifferentiation and disorganization (tufting) of the surface epithelium, and crypt abnormalities. The histological lesions were assessed semiquantitatively and compared with the clinical outcomes including dependence on PN.

RESULTS

Seven children, all from consanguineous parents, were studied for a median of 6.5 years. Three were permanently weaned off PN and experienced normal growth without nutritional assistance. Initial biopsies in all 3 children showed severe diffuse histological lesions. At weaning off PN, 2 of these 3 patients had persistent, although less diffuse, histological lesions.

CONCLUSIONS

Progressive weaning off PN is possible in some children with TE. In our experience, this favorable outcome was not predicted by histological lesion severity, although the lesions improved in some patients. New biomarkers for identifying the histological lesions and predicting the outcome would be useful.

Enteropathies of Infancy and Childhood

Intestinal biopsies constitute an ever-increasing portion of the pathologist's workload, accounting for nearly two-thirds of specimens accessioned yearly by the pathology department at The Children's Hospital of Philadelphia. The widespread use of endoscopy and gastrointestinal biopsies in current clinical practice presents the pathologist with a diversity of intestinal mucosal appearances corresponding to disease states of variable clinical severity, requiring close collaboration between clinician and pathologist for optimal interpretation. Many of the entities resulting in severe diarrhea of infancy have been recognized only in the last several decades, and although rare, the study of these disorders, especially when combined with the powerful methods of present-day genetics and molecular biology, has afforded important insights into enterocyte development and function, and intestinal immunity and tolerance. Other conditions once considered infrequent, such as celiac disease, have now been recognized to be much more common and can present with a wide range of pathologic features.

Extracutaneous manifestations and complications of inherited epidermolysis bullosa: part I. Epithelial associated tissues

Based upon case reports and small case series, it has been known for many years that some types and subtypes of inherited epidermolysis bullosa (EB) may be at risk for developing one or more extracutaneous complications. Many of these are associated with considerable morbidity; some may result in death. Only over the past few years have there been data generated from large, well characterized cohorts. However, these data, to date, have been published almost exclusively in the nondermatologic literature. Our objective is to provide dermatologists with a comprehensive review of each major extracutaneous complication with a summary of the pertinent literature and recommendations for evaluation and optimal management. Part I highlights epithelial associated tissues, and part II addresses other organs. Based on these reviews, the readership should gain a greater understanding of the types of complications that may occur, when they are most likely to develop, and the range of medical and surgical interventions that are currently available. It should also be possible for the reader to develop surveillance strategies based on an understanding of the published evidence-based data. The breadth and range of severity of complications that arise in some EB types and subtypes within the external eye, ear, nose, upper airway, and gastrointestinal and genitourinary tracts suggest that optimal management must be multidisciplinary. Given the unique knowledge that dermatologists have of this disease, we believe that the care of the EB patient should be under the direction of his or her dermatologist, who can best assist in timely referrals to those specialists who are most experienced in the care of specific extracutaneous problems.

Desquamative enteropathy and pyloric atresia without skin disease caused by a novel intracellular beta4 integrin mutation

BACKGROUND

Mutations in alpha6 or beta4 integrins (ITGA6, ITGB4) are known to cause junctional epidermolysis bullosa with pyloric atresia (JEB-PA), often lethal in infancy through skin desquamation. There is 1 report of pyloric atresia associated with a desquamatory enteropathy but without skin disease, of unknown molecular basis.

PATIENTS AND METHODS

We report 2 Kuwaiti siblings with pyloric atresia and life-threatening intestinal desquamation without significant skin abnormality. The older sibling died of intractable diarrhoea, and the younger sibling suffered episodes of massive protein-losing enteropathy, triggered by viral infections, in addition to obstructive uropathy. Mutation analysis was performed for ITGA6 and ITGB4 and expression of ITGA6 and ITGB4 protein was examined in skin and intestinal biopsies. Her serum also was incubated with normal intestine.

RESULTS

We identified a novel mutation in ITGB4, with homozygous deletion of a single residue (isoleucine 1314) within the intracellular plectin-binding domain. Expression of ITGA6 and ITGB4 within skin, duodenal, and colonic epithelium was normal or minimally reduced, in contrast to previous reports. Biopsies taken during relapse showed accumulation of immunoglobulin G and C1q within intestinal basement membrane, whereas immunoglobulin G from her serum bound to basement membrane of normal small intestine. Immunomodulatory therapy induced significant improvement following relapses.

CONCLUSIONS

ITGB4 mutation may induce a desquamative enteropathy in infancy without significant skin disease. A history of pyloric atresia is important in infants with severe chronic diarrhoeal disease and should prompt investigation for JEB-PA associated mutations. Acquired immune responses may exacerbate primary genetic disorders of epithelial adhesion and immunomodulatory therapy may be beneficial.

Gastrointestinal complications of epidermolysis bullosa in children

BACKGROUND

Epidermolysis bullosa (EB) is a group of inherited disorders characterized by skin and mucous membrane fragility. Gastrointestinal (GI) complications have been described in many types of EB and are responsible for significant morbidity.

OBJECTIVES

To delineate the nature and frequency of GI complications in a large cohort of paediatric patients with EB and to postulate why some complications occur more commonly in some specific subtypes.

METHODS

The case notes of 223 children with EB seen at a national referral centre were examined retrospectively for the presence of GI symptoms, investigations and interventions.

RESULTS

GI complications were present in 130/223 (58%) of all patients. In EB simplex, constipation and gastro-oesophageal reflux (GOR) were frequently observed. In junctional EB, failure to thrive and protein-losing enteropathy (PLE) were the prominent GI manifestations. Constipation was common in patients with dystrophic EB (DEB) requiring laxatives and in some cases fibre supplementation. GOR affected three-quarters of those with recessive DEB, two-thirds also having significant oesophageal strictures. Over half of patients with recessive DEB required gastrostomy insertion. Diarrhoea affected a small but significant proportion of children with recessive DEB with macroscopic and/or microscopic changes of colitis in the majority.

CONCLUSION

GI problems in EB are very common with subtype specificity for some of these complications. The occurrence of diarrhoea, PLE and colitis in the context of EB has not been highlighted previously, and may arise secondarily to antigenic exposure in the gut lumen as a result of mucosal fragility.

A new syndrome of tufting enteropathy and choanal atresia, with ophthalmologic, hematologic and hair abnormalities

Three siblings are reported with a syndrome of intractable diarrhea of infancy (owing to tufting enteropathy) and choanal atresia/stenosis. Additional components of this condition are a mild shortness of stature, a prominent and broad nasal bridge, micrognathia, single palmar creases, chronic corneal inflammation, episodic cytopenia, and abnormal hair texture. Intelligence is normal, and there is no immunodeficiency distinguishing this syndrome from that reported by Girault et al. (1994). Additional features that might occur in this syndrome include bifid uvula, preauricular pits, and 2/3 toe syndactyly. We compare this syndrome with previously reported intractable diarrhea syndromes and speculate on the developmental mechanisms that could account for many of the features demonstrated by this sibship.

Neonatal enteropathies: defining the causes of protracted diarrhea of infancy

The underlying causes of chronic diarrhea beginning early in life are increasingly well defined. Infectious and post-infectious enteropathies and food sensitive/allergic enteropathy account for the majority of cases. Recent attention has focused on characterizing defined entities, which cause protracted diarrhea in infants and young children. Disorders of intestinal ion transport usually present at birth following a pregnancy complicated by polyhydramnios. Intestinal mucosal biopsies show normal architect with intact villus-crypt axis. Neonatal enteropathies, by contrast, are characterized by blunting of the villi. These include microvillus inclusion disease, tufting enteropathy, autoimmune enteropathy and IPEX syndrome - and it is these conditions that are the subject of the current review.