If fructose is ingested, the enzymatic block at aldolase B causes an accumulation of fructose-1-phosphate which, over time, results in the death of liver cells.

[1] Symptoms of HFI include vomiting, convulsions, irritability, poor feeding as a baby, hypoglycemia, jaundice, hemorrhage, hepatomegaly, hyperuricemia and potentially kidney failure.

[5] Symptoms such as vomiting, nausea, restlessness, pallor, sweating, trembling and lethargy can also first present in infants when they are introduced to fruits and vegetables.

Deficiencies of fructokinase cause essential fructosuria, a clinically benign condition characterized by the excretion of unmetabolized fructose in the urine.

In HFI, the diagnosis of homozygotes is difficult, requiring a genomic DNA screening with allele-specific probes or an enzyme assay from a liver biopsy.

Stable patients without acute intoxication events are treated by careful dietary planning that avoids fructose and its metabolic precursors.