The fructosuria of this disease depends on the time and amount of fructose and sucrose intake. Since the disorder is asymptomatic and harmless it may go undiagnosed. Hereditary fructose intolerance is a potentially lethal disorder resulting from a lack of aldolase B which is normally present in the liver, small intestine and kidney cortex. The disorder is characterized by severe hypoglycemia and vomiting following fructose intake. Prolonged intake of fructose by infants with this defect leads to vomiting, poor feeding, jaundice, hepatomegaly, hemorrhage and eventually hepatic failure and death.
Patients remain symptom free on a diet devoid of fructose and sucrose.
These symptoms can take on a lethal course in neonates. Later in life episodes are triggered by fasting and febrile infections. This occurs through a series of steps. Entry of galactose carbon atoms into the glycolytic pathway. Classic galactosemia is a major symptom of two enzyme defects.