Copy-number variation of the neuronal glucose transporter gene SLC2A3 and age of onset in Huntington's disease.
Huntington's disease (HD) is a devastating neurodegenerative disorder which is inherited in an autosomal dominant manner. HD is caused by a trinucleotide CAG repeat expansion that encodes a polyglutamine stretch in the huntingtin (HTT) protein. Mutant HTT expression leads to a myriad of cellular dysfunctions culminating in neuronal loss and consequent motor, cognitive and psychiatric disturbances in HD patients. The length of the CAG repeat is inversely correlated with age of onset (AO) in HD patients, while environmental and genetic factors can further modulate this parameter. Here, we explored whether the recently described copy-number variation (CNV) of the gene SLC2A3-which encodes the neuronal glucose transporter GLUT3-could modulate AO in HD. Strikingly, we found that increased dosage of SLC2A3 delayed AO in an HD cohort of 987 individuals, and that this correlated with increased levels of GLUT3 in HD patient cells. To our knowledge this is the first time that CNV of a candidate gene has been found to modulate HD pathogenesis. Furthermore, we found that increasing dosage of Glut1-the Drosophila melanogaster homologue of this glucose transporter-ameliorated HD-relevant phenotypes in fruit flies, including neurodegeneration and life expectancy. As alterations in glucose metabolism have been implicated in HD pathogenesis, this study may have important therapeutic relevance for HD.
Department of Genetics, University of Leicester, Leicester, UK Cell and Molecular Neuroscience Unit, Instituto de Medicina Molecular, Lisbon, Portugal.
Angelica
A
Vittori
Department of Genetics, University of Leicester, Leicester, UK.
Carlo
C
Breda
Department of Genetics, University of Leicester, Leicester, UK.
Mariaelena
M
Repici
Department of Neurology, University of Ulm, Ulm, Germany.
Michael
M
Orth
Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands.
Raymund A C
RA
Roos
Cell and Molecular Neuroscience Unit, Instituto de Medicina Molecular, Lisbon, Portugal Instituto de Fisiologia, Faculdade de Medicina da Universidade de Lisboa, Lisbon, Portugal Department of NeuroDegeneration and Restorative Research, University Medical Center Göttingen, Göttingen, Germany.
Tiago F
TF
Outeiro
Department of Genetics, University of Leicester, Leicester, UK fg36@le.ac.uk ejh33@le.ac.uk.
Flaviano
F
Giorgini
Department of Genetics, University of Leicester, Leicester, UK fg36@le.ac.uk ejh33@le.ac.uk.
Edward J
EJ
Hollox
D017668:Age of Onset; D000818:Animals; D002460:Cell Line; D015331:Cohort Studies; D056915:DNA Copy Number Variations; D004195:Disease Models, Animal; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000378:metabolism*; D005260:Female; D018628:Gene Dosage; D051274:Glucose Transporter Type 3 / Q000235:genetics* / Q000378:metabolism*; D006801:Humans; D006816:Huntington Disease / Q000453:epidemiology* / Q000235:genetics* / Q000473:pathology; D008297:Male; D010802:Phylogeny; D015854:Up-Regulation
D029721:Drosophila Proteins; D051274:Glucose Transporter Type 3