Hereditary Fructose Intolerance Diagnosed in Adulthood

Abstract

Hereditary fructose intolerance (HFI) is an autosomal recessive disorder caused by a mutation in the aldolase B gene. HFI patients exhibit nausea, vomiting, abdominal pain, hypoglycemia, and elevated liver enzymes after dietary fructose exposure. Chronic exposure might lead to failure to thrive, liver failure, renal failure, and, eventually, death. HFI usually manifests in infants when they are being weaned off of breastmilk. Because HFI has an excellent prognosis when patients maintain a strict restrictive diet, some patients remain undiagnosed due to the voluntary avoidance of sweet foods. In the past, HFI was diagnosed using a fructose tolerance test, liver enzyme assays or intestinal biopsy specimens. Currently, HFI is diagnosed through the analysis of aldolase B mutations. Here, HFI was diagnosed in a 41-year-old woman who complained of sweating, nausea, and vomiting after consuming sweets. She had a compound heterozygous mutation in the aldolase B gene; gene analysis revealed pathogenic nonsense (c.178C>T, p.Arg60Ter) and frameshift (c.360_363delCAAA, p.Asn120LysfsTer32) variants. This is the first report of a Korean HFI patient diagnosed in adulthood.

Keywords: Aldolase B; Fructose intolerance.

Fig. 1

Pathophysiology of hereditary fructose intolerance (HFI). Deficiency of aldolase B leads to the accumulation of fructose 1-phosphate (F 1-P), which causes direct toxicity to the liver and kidney. Glycolysis and gluconeogenesis are downregulated due to the inhibition of DHAP and glyceraldehyde, which enters the pathway. Moreover, ATP is depleted as phosphorylation continues, blocking all processes requiring ATP. ATP, adenosine triphosphate; ADP, adenosine diphosphate; DHAP, dihydroxyacetone phosphate.