A summary of molecular genetic findings in fructose-1,6-bisphosphatase deficiency with a focus on a common long-range deletion and the role of MLPA analysis.

René Santer,Ania C. Muntau,Esther Maier,Inga Vater,Marcel du Moulin,Beat Steinmann,Tatevik Shahinyan

doi:10.1186/s13023-016-0415-1

Abstract

BackgroundFructose-1,6-bisphosphatase deficiency is a rare inborn error of metabolism affecting gluconeogenesis with only sporadic reports on its molecular genetic basis.ResultsWe report our experience with mutation analysis in 14 patients (13 families) with fructose-1,6-bisphosphatase deficiency using conventional Sanger sequencing and multiplex ligation-dependent probe amplification analysis, and we provide a mutation update for the fructose bisphosphatase-1 gene (FBP1). Mutations were found on both chromosomes in all of our 14 patients including 5 novel mutations. Among the novel mutations is a 5412-bp deletion (c.-24-26_170 + 5192del) including the entire coding sequence of exon 2 of FBP1 that was repeatedly found in patients from Turkey and Armenia which may explain earlier poorly defined findings in patients from this area. This deletion can be detected with specific primers by generation of a junction fragment and by MLPA and SNP array assays. MLPA analysis was able to detect copy number variations in two further patients, one heterozygous for a deletion within exon 8, another heterozygous for a novel deletion of the entire FBP1 gene.ConclusionsBased on our update for the FBP1 gene, currently listing 35 mutations worldwide, and knowledge of PCR conditions that allow simple detection of a common FBP1 deletion in the Armenian and Turkish population, molecular genetic diagnosis has become easier in FBP1 deficiency. Furthermore, MLPA analysis may plays a useful role in patients with this disorder.Electronic supplementary materialThe online version of this article (doi:10.1186/s13023-016-0415-1) contains supplementary material, which is available to authorized users.

Highlights

Fructose-1,6-bisphosphatase deficiency is a rare inborn error of metabolism affecting gluconeogenesis with only sporadic reports on its molecular genetic basis
fructose bisphosphatase-1 gene (FBP1) deficiency is generally believed to be very rare with an estimated incidence between 1 : 350,000 and
We report results of mutation analysis of our laboratory, describe how we have characterized a common exon 2 deletion detected in patients with Turkish or Armenian ethnic background, and provide polymerase chain reaction (PCR) conditions for verification of this deletion which is otherwise not detectable by standard sequencing techniques

Summary

Introduction

Fructose-1,6-bisphosphatase deficiency is a rare inborn error of metabolism affecting gluconeogenesis with only sporadic reports on its molecular genetic basis. Fructose-1,6-bisphosphatase (FBP1) deficiency [OMIM: 229700], first described in 1970 [1], is an inborn error of gluconeogenesis. FBP1 deficiency is inherited in an autosomal recessive way. It is caused by mutations within the FBP1 gene (OMIM: 611570) which spans approx. Only a small number of mutations has been published and among them, c.959dupG has been reported to be the most common one in Caucasians and in patients from Japan and China [5, 7,8,9]

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