Recent progress in congenital diarrheal disorders.

Congenital diarrheal disorders (CDD) are a group of rare enteropathies related to specific genetic defects. Infants with these disorders have chronic diarrhea, frequently requiring parenteral nutrition support. Etiologies and prognoses are variable. We propose a new classification of CDD into four groups, taking into account the specific etiology and genetic defect: 1) defects in digestion, absorption, and transport of nutrients and electrolytes; 2) disorders of enterocyte differentiation and polarization; 3) defects of enteroendocrine cell differentiation; and 4) dysregulation of the intestinal immune response. The present review focuses on the recent advances made in understanding the pathophysiology of CDD that could potentially improve the clinical approach to these conditions.