A patient may demonstrate intolerance to fructose from birth if a he or she inherits a certain mutation affecting the enzyme aldolase B..


Clinical features:

(1) onset of symptoms with weaning and after intake of fruit or processed foods

(2) chronic diarrhea with abdominal pain and flatulence

(3) fatigue and apathy

(4) enuresis and encopresis

(5) delayed language development

(6) hypoglycemia following fructose exposure

(7) absence of dental caries

(8) dietary avoidance of fructose-containing fruits, drinks and foods

(9) other family members may be affected

(10) life-threatening hypoglycemia during a fructose challenge, either accidental or intentional

(11) life-threatening hypoglycemia following administration of parenteral nutrition containing fructose


The diagnosis can be suspected based on clinical findings and clinical improvement with avoidance of fructose. A more complete description is given in Chapter 43.


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