A1 Refereed original research article in a scientific journal
A Partial Loss-of-Function Variant in AKT2 is Associated with Reduced Insulin-Mediated Glucose Uptake in Multiple Insulin Sensitive Tissues: a Genotype-Based Callback Positron Emission Tomography Study
Authors: Aino Latva-Rasku, Miikka-Juhani Honka, Alena Stančáková, Heikki A. Koistinen, Johanna Kuusisto, Li Guan, Alisa K Manning, Heather Stringham, Anna L Gloyn, Cecilia M Lindgren, the T2D-GENES Consortium, Francis S Collins, Karen L Mohlke, Laura J Scott, Tomi Karjalainen, Lauri Nummenmaa, Michael Boehnke, Pirjo Nuutila, Markku Laakso
Publication year: 2018
Journal: Diabetes
Volume: 67
Issue: 2
First page : 334
Last page: 342
Number of pages: 9
ISSN: 0012-1797
DOI: https://doi.org/10.2337/db17-1142
Self-archived copy’s web address: https://research.utu.fi/converis/portal/detail/Publication/27208040
Rare fully penetrant mutations in AKT2 are an established cause of monogenic disorders of glucose metabolism. Recently, a novel partial loss-of-function AKT2 coding variant (p.Pro50Thr) was identified that is nearly specific to Finns (frequency 1.1%), with the low-frequency allele associated with an increase in fasting plasma insulin level and risk of type 2 diabetes. The effects of p.Pro50Thr on insulin-stimulated glucose uptake (GU) in the whole body and in different tissues have not previously been investigated. We identified carriers (N=20) and matched non-carriers (N=25) for this allele in the population-based METSIM study and invited these individuals back for positron emission tomography study with [18F]-fluorodeoxyglucose during euglycemic hyperinsulinemia. When we compared p.P50T/AKT2 carriers to non-carriers, we found a 39.4% reduction in whole body GU (P=0.006) and a 55.6% increase in the rate of endogenous glucose production (P=0.038). We found significant reductions in GU in multiple tissues: skeletal muscle (36.4%), liver (16.1%), brown adipose (29.7%), and bone marrow (32.9%), and increases of 16.8-19.1% in 7 tested brain regions. These data demonstrate that the P50T substitution of AKT2 influences insulin-mediated GU in multiple insulin sensitive tissues, and may explain, at least in part, the increased risk of type 2 diabetes in p.P50T/AKT2 carriers.
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