Hereditary fructose intolerance in Brazilian patients

INTRODUCTION: Hereditary fructose intolerance (HFI) is a rare inborn error of carbohydrate metabolism, autosomal recessive, caused by mutations in the gene ALDOB, leading to deficiency of aldolase B. Symptoms begin in the first months of life with the introduction of complementary foods containing fructose, sucrose or sorbitol, often with vomiting, feeding problems and failure to thrive. Prolonged exposure may cause liver and kidney failure, which can lead to death. Treatment consists in removing the toxic sugars of diet. MATERIALS AND METHODS: Clinical and molecular characterization of four unrelated patients from the State of Minas Gerais, Brazil, all children from non-consanguineous parents. RESULTS AND DISCUSSION: Age at diagnosis was between 10 and 32 months and the severity of the disease correlated with the increasing of age at diagnosis. The predominant symptoms were vomiting, weight loss, and hepatomegaly. Severe renal tubular acidosis manifested in one child. All patients had remission of symptoms after dietary modification. The sequencing of the ALDOB gene identified one homozygous patient for the mutation c.524C > A (p.A175D), while the others were compound heterozygous for c.360_363delCAAA (p.N120KfsX32), c.178C > T (p.R60X) mutations, c.448G > C (p.A150P) and c.524C > A (p.A175D). Clinical improvement of patients after dietary treatment is suggestive of the diagnosis, confirmed by molecular analysis. The prevalence of mutations found in our Brazilian patients is different from those of international literature.