Excess maternal transmission of variants in the THADA gene to offspring with type 2 diabetes.

AIMS/HYPOTHESIS: Genome-wide association studies (GWAS) have identified more than 65 genetic loci associated with risk of type 2 diabetes. However, the contribution of distorted parental transmission of alleles to risk of type 2 diabetes has been mostly unexplored. Our goal was therefore to search for parent-of-origin effects (POE) among type 2 diabetes loci in families. METHODS: Families from the Botnia study (n = 4,211, 1,083 families) were genotyped for 72 single-nucleotide polymorphisms (SNPs) associated with type 2 diabetes and assessed for POE on type 2 diabetes. The family-based Hungarian Transdanubian Biobank (HTB) (n = 1,463, >135 families) was used to replicate SNPs showing POE. Association of type 2 diabetes loci within families was also tested. RESULTS: Three loci showed nominal POE, including the previously reported variants in KCNQ1, for type 2 diabetes in families from Botnia (rs2237895: p POE = 0.037), which can be considered positive controls. The strongest POE was seen for rs7578597 SNP in the THADA gene, showing excess transmission of the maternal risk allele T to diabetic offspring (Botnia: p POE = 0.01; HTB p POE = 0.045). These data are consistent with previous evidence of allelic imbalance for expression in islets, suggesting that the THADA gene can be imprinted in a POE-specific fashion. Five CpG sites, including those flanking rs7578597, showed differential methylation between diabetic and non-diabetic donor islets. CONCLUSIONS/INTERPRETATION: Taken together, the data emphasise the need for genetic studies to consider from which parent an offspring has inherited a susceptibility allele.

Sex influenced association of directly measured insulin sensitivity and serum transaminase levels: Why alanine aminotransferase only predicts cardiovascular risk in men?

BACKGROUND: Non alcoholic fatty liver disease (NAFLD) is an independent cardiovascular (CV) risk factor which is closely associated with insulin resistance measured by both direct or indirect methods. Gender specific findings in the relationship between alanine aminotransferase (ALT) and CV disease, the prevalence of NAFLD and type 2 diabetes (T2DM) have been published recently. The aim of the present study was to explore the gender aspects of the association between insulin sensitivity, liver markers and other metabolic biomarkers in order to elucidate the background behind the sex influenced difference in both NAFLD, T2DM and their association with CV risk. PATIENTS AND METHODS: 158 female (47 normal and 111 impaired glucose intolerant) and 148 male (74 normal and 74 impaired glucose tolerant) subjects were included (mean age: 46.5 ± 8.31 vs. 41.6 ± 11.3, average Hba1c < 6.1 %, i.e. prediabetic population, drug naive at the time of the study). Subjects underwent a hyperinsulinemic normoglycemic clamp to determine muscle glucose uptake (M3), besides liver function tests and other fasting metabolic and anthropometric parameters were determined. RESULTS: Significant bivariate correlations were found between clamp measured M3 and all three liver enzymes (ALT, aspartate aminotransferase and gamma-glutamyl transferase) in both sexes. When data were adjusted for possible metabolic confounding factors correlations ceased in the male population but stayed significant in the female group. Feature selection analysis showed that ALT is an important attribute for M3 in the female but not in male group (mean Z: 3.85 vs. 0.107). Multiple regression analysis confirmed that BMI (p < 0.0001) and ALT (p = 0.00991) significantly and independently predicted clamp measured muscle glucose uptake in women (R(2) = 0.5259), while in men serum fasting insulin (p = 0.0210) and leptin levels (p = 0.0294) but none of the liver enzymes were confirmed as significant independent predictors of M3 (R(2) = 0.4989). CONCLUSION: There is a gender specific association between insulin sensitivity, metabolic risk factors and liver transaminase levels. This might explain the sex difference in the predictive role of ALT elevation for CV disease. Moreover, ALT may be used as a simple diagnostic tool to identify insulin resistant subjects only in the female population according to our results.

[The effect of genetic risk of diabetes on the correlations in bone and energy homeostasis]. / A genetikai diabeteskockázat hatása a csontanyagcsere-energia-háztartás kapcsolatokra.

INTRODUCTION: Type 2 diabetes is associated with increased risk of bone fractures, and the connection between bone remodeling and carbohydrate homeostasis is decoupled. It is not known whether these phenomena are the consequence of the deteriorating glucose metabolism, and the increasing insulin resistance or they belong to the genetic risk of type 2 diabetes. AIM: The aim of the authors was to clarify the impact of genetic risk on bone and carbohydrate homeostasis connections. METHOD: Hyperinsulinemic-normoglycemic clamps, and oral and iv. glucose loads were done to select 18 metabolically healthy females with first degree type 2 diabetic relatives -and 26 without diabetic relatives. RESULTS: The connections between total body glucose utilization and the activity of the bone metabolic unit were missing in healthy females with the genetic risk of type 2 diabetes, like in those with manifest diabetes. In this risk group the level of low-density-large molecular sized LDL lipids were decreased, while the high-density LDL group with low molecular size was increased. The latter change was in significant connection with increased interleukin-6 levels and increased bone resorption within the bone metabolic unit. CONCLUSIONS: These data suggest that the missing connection between glucose and bone metabolism is not the consequence of the developing insulin resistance and deteriorating glucose metabolism, but rather it belongs to the inherited diabetes risk. The etiology of this early alteration, which develops prior to glucose intolerance and insulin resistance is unknown and needs further investigations.

[Metabolic differences in healthy first-degree female relatives of type 2 diabetic patients]. / Anyagcsere-eltérések a 2-es típusú cukorbetegek egészséges, elsofokú norokonaiban.

INTRODUCTION: Today the prevalence of type 2 diabetes reached an epidemic level. It is known that type 2 diabetes could only be prevented before the manifestation, during the "prediabetic" state, urging the development of diagnostic tests to recognize the group at risk in time. AIM: The authors explored metabolic differences between healthy, normal glucose tolerant, normal insulin resistant females having first degree relatives with and without type 2 diabetes. METHOD: Healthy, normal insulin sensitive females without (n = 26) and with (n = 18) type 2 diabetic relatives were investigated. RESULTS: Healthy females with first degree diabetic relatives had lower low density lipoproteins and higher high density lipoproteins as well as higher glucose and insulin levels at the 120 min of oral glucose test as compared to those without first degree diabetic relatives. CONCLUSIONS: These results suggest that the appearance of insulin resistance is preceded by hepatic insulin resistance and impaired lipid metabolism in the symptom-free prediabetic period of genetically susceptible females.

Lipid-Associated Variants near ANGPTL3 and LPL Show Parent-of-Origin Specific Effects on Blood Lipid Levels and Obesity.

Parent-of-origin effects (POE) and sex-specific parental effects have been reported for plasma lipid levels, and a strong relationship exists between dyslipidemia and obesity. We aim to explore whether genetic variants previously reported to have an association to lipid traits also show POE on blood lipid levels and obesity. Families from the Botnia cohort and the Hungarian Transdanubian Biobank (HTB) were genotyped for 12 SNPs, parental origin of alleles were inferred, and generalized estimating equations were modeled to assess parental-specific associations with lipid traits and obesity. POE were observed for the variants at the TMEM57, DOCK7/ANGPTL3, LPL, and APOA on lipid traits, the latter replicated in HTB. Sex-specific parental effects were also observed; variants at ANGPTL3/DOCK7 showed POE on lipid traits and obesity in daughters only, while those at LPL and TMEM57 showed POE on lipid traits in sons. Variants at LPL and DOCK7/ANGPTL3 showed POE on obesity-related traits in Botnia and HTB, and POE effects on obesity were seen to a higher degree in daughters. This highlights the need to include analysis of POEs in genetic studies of complex traits.

Altered gene expressions in periferal blood cells of first-degree non-diabetic relatives of type 2 diabetic patients. / [Génexpressziós eltérések keringo fehérvérsejtekben a 2-es típusú cukorbetegek elsofokú, anyagcseréjüket illetoen egészséges rokonaiban].

Introduction and aim: We were looking for altered gene expression on peripheral blood cells significant to type 2 diabetes causing the world epidemic. Method: Muscle biopsy samples of healthy volunteers with (n = 6) or without (n = 6) first degree type 2 diabetic relatives were analyzed by mRNS microarray. After confirmation of microarrays results by quantitative real-time PCR, the expression of eight differently expressed genes were further investigated on peripheral blood cells of 58 healthy volunteers without diabetic relatives and 58 healthy ones with first-degree type 2 diabetic relatives. Results: The expressions of SERPINF1 gene were significantly lover in blood cells both from females (relative quantification: FC - female: = 0.69, p<6*10-3) and males (FC - male: = 0.65, p<2*10-3) with diabetic relatives. This change may not be the consequence of worsening metabolic state as it was identical in cells of type 2 diabetic patients and in healthy volunteers with diabetic relatives. We suggest that the altered SERPINF1 gene expression in peripheral mononuclear blood cells could be a genetic definiteness. Conclusion: With the help of SERPINF1 gene expression in white blood cells and lipid and biochemical blood parameters we suggest a mathematical formula for the augury of type 2 diabetes that should be checked on a larger population, but we hope it could be used as a diabetic marker. The expression of LAMP2 gene did not differ between the two healthy groups, but it showed a maternal parent of origin effect. In the case of maternal inheritance, we found higher LAMP2 expression suggesting that gene from the mother has a determining effect. Orv Hetil. 2020; 161(18): 738-746.