DIABETES MELLITUS: A COMPLEX METABOLIC DISORDER.EXPLORING THE DISEASE THROUGH FRUCTOSAMINE 3-KINASE GENE ANALYSIS
Tesi di Dottorato
Data di Pubblicazione:
2015
Citazione:
DIABETES MELLITUS: A COMPLEX METABOLIC DISORDER.EXPLORING THE DISEASE THROUGH FRUCTOSAMINE 3-KINASE GENE ANALYSIS / F. Avemaria ; coordinatore: F. Bonomi ; tutor: A. Mosca, P. Carrera. DIPARTIMENTO DI FISIOPATOLOGIA MEDICO-CHIRURGICA E DEI TRAPIANTI, 2015 Dec 09. 28. ciclo, Anno Accademico 2015. [10.13130/avemaria-francesca_phd2015-12-09].
Abstract:
Diabetes Mellitus is the most prevalent metabolic disorder characterized by chronic hyperglycemia due to primary defects in insulin secretion and/or insulin function. In the last few decades the notion of diabetes has widened, ascertain that the present subdivision into type 1 (T1DM) and type 2 (T2DM) diabetes is a gross oversimplification. Both forms of diabetes seem to result from a complex interplay between genes and environment. Advance technologies have revolutionized the search for genetic influences on complex traits. Genomewide association studies (GWAS) and GWAS meta-analyses have been the most efficient way to identify new T2DM genes. However, despite these advances, the overall effect attributed to these loci is low and their contribution is of little clinical usefulness compared to evaluation of classical risk factors such as body mass index (BMI), age and family history. Therefore, evaluation of glycemic control remain the primary target for diabetes treatments. However, understanding and utilization of single gene effects on specific traits that conglomerate into a complex phenotype is currently the best way to understand the genetic basis at functional level and could results in a possible advantage for disease prevention and management.
In this light, to explore the complexity of this disorder and to give some hints in the pathogenesis of diabetes, we have followed a candidate gene approach by studying the Fructosamine 3-kinase (FN3K) gene, whose product is implicated in non-enzymatic glycation of proteins, in an Italian cohort of diabetic individuals.
Glycation has long been considered irreversible. Thus, the identification of an enzyme, FN3K, able to reverse this process by decomposing fructosamine 3-phosphate to 3-deoxyglucosone, inorganic phosphate and an amine, opened the perspective that fructosamines could be physiologically removed by proteins, suggesting a protective role in the development of diabetic complications and other pathologies characterized by high fructosamines/AGEs levels.
First aim of the present study was to accomplish the analysis of the FN3K gene in a well clinically characterized group of Italian individuals with diabetes (35 T1DM and 35 T2DM) belonging to ADAG study and 33 healthy subjects, by analyzing its promoter region. Then, the FN3K gene (promoter region and all six exons with corresponding intron/exon boundaries) were analyzed in additional 80 T2DM subjects, followed since long time in diabetic clinic.
The molecular screening revealed the presence of 15 different genetic variants. Four of them represented new mutations: the c.2 T>A (p.M1?) in the translation starting codon; the c.465 G>A (p.P115=) located in a consensus sequence for the splicing site; the c.559 C>T (p.R187*) leading to the formation of a truncated protein; the missense mutation c.716 A>G (p.Y239C) in exon 6. Presence of these variants were excluded from control group using DHPLC analysis. Other 11 variants identified were polymorphisms; of them 3 were new: the IVS2-27 A>G in intron 2; the c.421 C>T and c.429delATCGGAG in the promoter region. The remaining 8 were polymorphisms already described: c. -232 A>T and c.-385 A>G in the promoter region; c.187 A>C (p.R63=) in exon 2; c.900 C>G (p.S300=) and c.906 C>T (p.G302=) in exon 6; polymorphisms IVS+26 G>A, IVS+31 A>T and IVS4-9-11delTTG were present in non coding regions of the FN3K gene (intron 2, intron 2 and intron 4, respectively).
An RNA expression study was performed on new variants (c.2 T>A; c.465 G>A; c.559 C>T and c.716 A>G) in order to confirm the hypothesis on pathogenicity of these variants found at genomic level. Furthermore, mutations c.559 C>T (p.R187*) and c.716 A>G (p.Y239C) were analyzed in a familial context. The RNA analysis didnft confirm
Tipologia IRIS:
Tesi di dottorato
Elenco autori:
F. Avemaria
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