# Co‐occurrence of collagenous gastrointestinal disease in siblings in early childhood: New insight into a rare condition

## TL;DR

This paper reports two siblings diagnosed with a rare GI condition, offering new insights into its pediatric presentation and connection to microscopic colitis.

## Contribution

The study presents the first reported cases of collagenous GI disease in siblings during early childhood.

## Key findings

- Both siblings showed gastric and colonic involvement with distinct clinical and histological features.
- The findings expand understanding of collagenous GI disease's pediatric phenotype and its link to microscopic colitis.

## Abstract

Collagenous gastrointestinal (GI) disease is a rare inflammatory condition characterized by subepithelial collagen deposition and inflammatory cell infiltrates of the GI mucosa, which typically occurs in the stomach in children. There are few published reports of more extensive involvement in children, and descriptions of familial involvement are rare, with no previous reported cases of affected siblings in early childhood. We describe two siblings with contrasting medical backgrounds, who were simultaneously diagnosed with collagenous GI disease in early childhood. Both children demonstrated gastric and colonic involvement on serial endoscopies, however, had distinct patterns of clinical presentation, disease course, and histological progression, providing new insights into the pediatric phenotype of collagenous GI disease and further, its relationship to microscopic colitis. Although rare, this condition should be considered as a differential in children presenting with severe or refractory iron deficiency anemia, chronic non‐bloody watery diarrhea, or unexplained nonspecific chronic abdominal pain.