<prompt> Familial fructokinase deficiency causes no symptoms because:Hexokinase can phosphorylate fructoseLiver aldolase can metabolize itExcess fructose does not escape into the urineExcess fructose is excreted through feces  <response>: Fructose metabolism Fructokinase is the first enzyme for fructose metabolism. It conves fructose to fructose-1-P. In Fructokinase deficiency, Hexokinase a non specific enzyme can phosphorylate fructose as well as other sugars but it has high km low affinity for fructose. Glucose is the true substrate for this enzyme. Fructose 6-phosphate - the end product of Hexokinase reaction can enter glycolytic pathway to be utilized fuher, so it does not accumulate to produce toxic effects. EXTRA EDGE- Fructokinase deficiency causes Essential Fructosuria, while Aldolase B deficiency causes Hereditary Fructose Intolerance 