FODMAPs are a discrete group of carbohydrates described as ‘fermentable’ owing to their availability for fermentation in the colon, which is either due to the absence, or reduced concentration, of suitable hydrolase enzymes for digestion (for example, lactase deficiency), or in the case of monosaccharides because of incomplete absorption in the small intestine. Here, LCT is linked to hyperinsulinemic hypoglycemia, familial, 4.