Microvillous Inclusion Disease: An Evolving Condition

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.

Neonatal Enteropathies: Defining the Causes of Protracted Diarrhea of Infancy

Sherman,

Mitchell,

Cutz

2004

Microvillous Atrophy

Perry

Bensallah

Martinez-Vinson

et al. 2014

Mutations in Myosin 5B in Children With Early‐onset Cholestasis

Cockar¹,

Foskett

Strautnieks

et al. 2020

Objectives: Mutations in Myosin 5B (MYO5B) are known to be associated with microvillous inclusion disease (MVID) a genetic cause of neonatal intractable diarrhoea. More recently, they have been reported in children with cholestasis but without typical gastrointestinal symptoms of MVID. We describe our series of children with cholestasis and mutations in MYO5B. Methods: Clinical, laboratory, and histological data were collected from patients with cholestasis and pathogenic mutations in MYO5B, found by next generation sequencing (NGS) but with minimal gastrointestinal disease. Results: Six patients (3 boys) were identified. Median age at presentation was 19 months (range, 3–92). Presenting features were jaundice, pale stools, pruritus, and failure to thrive. Patients 5 and 6 had intractable diarrhoea until the age of 3 and 7 years, respectively, but currently are on full enteral diet with no intestinal symptoms. Median values for serum total bilirubin were 55 μmol/L (2–500), alanine aminotransferase 73I IU/L (32–114), γ-glutamyltransferase 7 IU/L (7–10), and serum bile acids 134 μmol/L (18–274). Three patients underwent 1 or more types of biliary diversion for symptom control. Median follow-up was 5 years (2–22). At most recent follow-up, they all reported pruritus while on antipruritics. Patient 1 had a liver transplant. Conclusions: We identified 6 patients, with mutations in MYO5B, early-onset cholestasis and pruritus, with variable response to biliary diversion without typical MVID.