This section addresses the exchange of experiences and reports on advances in diagnosing and treating digestive conditions which share common clinical features but have special pathogenesis. As an example, inflammatory bowel disease is more and more common in the pediatric population. However, its very early onset (especially before 5 years of age) frequently has a monogenetic (several phenotypes have been described) that require different therapeutic approaches from later onset. This is also true for other conditions and we hope to help disseminate this knowledge. Articles on these conditions should include a strong translational component. Detailed reviews on rare GI conditions are also welcome.