Night Blindness in Cystic Fibrosis: The Key Role of Vitamin A in the Digestive System.

Vitamin A is a fundamental micronutrient that regulates various cellular patterns. Vitamin A deficiency (VAT) is a worldwide problem and the primary cause of nocturnal blindness especially in low income countries. Cystic fibrosis (CF) is a known risk factor of VAD because of liposoluble vitamin malabsorption due to pancreatic insufficiency. We describe a case of a 9-year-old girl who experienced recurrent episodes of nocturnal blindness due to profound VAD. This little girl is paradigmatic for the explanation of the key role of the gut-liver axis in vitamin A metabolism. She presents with meconium ileus at birth, requiring intestinal resection that led to a transient intestinal failure with parenteral nutrition need. In addition, she suffered from cholestatic liver disease due to CF and intestinal failure-associated liver disease. The interaction of pancreatic function, intestinal absorption and liver storage is fundamental for the correct metabolism of vitamin A.