Genetic analysis of patients with fructose-1,6-bisphosphatase deficiency

Franciele Cabral Pinheiro, Fernanda Sperb-Ludwig, Rodrigo Ligabue-Braun, Lavínia Schüler-Faccini, Carolina Fischinger Moura de Souza, Filippo Vairo, Ida Vanessa Doederlein Schwartz

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

Introduction: Fructose-1,6-bisphosphatase deficiency (FBPase deficiency) is a rare inborn error of metabolism that affects gluconeogenesis. Ketotic hypoglycemia is the main symptom and can occur at any age, usually after long periods of fasting or during illness. The diagnosis may be achieved by measurement of the enzyme activity in a liver sample, but FBP1 analysis has become the most common approach. Aim: To characterize the genotype of Southern Brazilian FBPase-deficient patients. Methodology: The FBP1 gene of six unrelated patients (one had consanguineous parents) with previous diagnoses of FBPase deficiency (enzymatic, pts A, B, D, E; genetic through Next-Generation Sequencing-NGS, pt F; enzymatic and Sanger sequencing, pt C) was first analyzed through NGS. Pathogenic variants found in NGS were confirmed by Sanger sequencing. The pathogenicity of novel missense variants was evaluated through in silico analysis. Results: Five patients (pt A, B, D, E, F) had their genotype identified by NGS, all of them being homozygous. In Pt C, NGS detected only one pathogenic variant. Among the 11 alleles analyzed, only three variants were found, two being novel: c.958G > A and c.986T > C. In silico analysis indicated the pathogenicity of both variants. Interestingly, the three variants seem to be linked to specific haplotypes, indicating that an endogamy effect may be acting on these alleles in the population of Southern Brazil. Conclusions: Our data suggest that NGS is a good tool for the diagnosis of FBPase deficiency. Variants c.958G > A and c.986T > C are the most prevalent variants in the country.

Original languageEnglish (US)
Pages (from-to)102-109
Number of pages8
JournalGene
Volume699
DOIs
StatePublished - May 30 2019

Keywords

  • FBP1
  • FBPase deficiency
  • Inborn errors of fructose metabolism
  • IonTorrent platform
  • Molecular diagnosis

ASJC Scopus subject areas

  • Genetics

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