Hypophosphatemic rickets: presenting features of fanconi-bickel syndrome.
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ABSTRACT:
SUBMITTER: Roy M
PROVIDER: S-EPMC3420661 | biostudies-literature | 2011
REPOSITORIES: biostudies-literature
Publications
Hypophosphatemic rickets: presenting features of fanconi-bickel syndrome.
Roy Mahua M Bose K K Paul D K DK Anand Puja P
Case reports in pathology 20111018
Fanconi-Bickel Syndrome (FBS) is a rare variety of glycogen storage disease (GSD). Characterized by massive hepatomegaly due to glycogen accumulation, severe hypophosphatemic rickets, and marked growth retardation due to proximal renal tubular dysfunction. We report a young boy presented as hypophosphatemic rickets with hepatomegaly and subsequently diagnosed as FBS. ...[more]
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Project description:Fanconi-Bickel syndrome is a rare inherited disorder characterized by hepatorenal glycogen accumulation, renal tubular dysfunction, growth failure, and impaired utilization of glucose and galactose. We report the first two children with Fanconi-Bickel syndrome from Pakistan who presented with classical features of Fanconi-Bickel Syndrome. Both patients were found to be homozygous for a single nucleotide deletion in the SLC2A2 gene defined as c.339delC. This mutation was previously described in an Arab patient who was initially presented as permanent neonatal diabetes mellitus before developing classical features of Fanconi-Bickel syndrome.
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Project description:Fanconi-Bickel Syndrome (FBS) is a rare disorder of carbohydrate metabolism that is characterized by the accumulation of glycogen mainly in the liver. It is inherited in an autosomal recessive manner due to mutations in the SLC2A2 gene. SLC2A2 encodes for the glucose transporter GLUT2 and is expressed in tissues that are involved in glucose homeostasis. The molecular mechanisms of dysglycemia in FBS are still not clearly understood. In this study, we report two cases of FBS with classical phenotypes of FBS associated with dysglycemia. Genomic DNA was extracted and analyzed by whole-genome and Sanger sequencing, and patient PBMCs were used for molecular analysis. One patient had an exonic SLC2A2 mutation (c.1093C>T in exon 9, R365X), while the other patient had a novel intronic SLC2A2 mutation (c.613-7T>G). Surprisingly, the exonic mutation resulted in the overexpression of dysfunctional GLUT2, resulting in the dysregulated expression of other glucose transporters. The intronic mutation did not affect the coding sequence of GLUT2, its expression, or glucose transport activity. However, it was associated with the expression of miRNAs correlated with type 1 diabetes mellitus, with a particular significant overexpression of hsa-miR-29a-3p implicated in insulin production and secretion. Our findings suggest that SLC2A2 mutations cause dysglycemia in FBS either by a direct effect on GLUT2 expression and/or activity or, indirectly, by the dysregulated expression of miRNAs implicated in glucose homeostasis.
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