Open-array analysis of genetic variants in Egyptian patients with type 2 diabetes and obesity

Association between FTO gene polymorphism and obesity in down syndrome children

Children with Down syndrome (DS) have a higher incidence of overweight and obesity compared to typically developing peers. The fat mass and obesity-associated gene (FTO) is one of the early identified genes linked to obesity in various populations. To date, the FTO rs17817449 gene polymorphism has not been investigated in overweight/obese-DS (ODS) individuals. The current study aimed to explore the potential association between the FTO rs17817449 gene polymorphism and obesity-related markers, and to evaluate the ability of this polymorphism in the prediction of overweight/obesity in DS children and adolescents. This case-control study included 100 DS children under the age of 18, classified into three groups according to BMI-percentile; 50 non-obese DS (NODS), 24 overweight DS, and 26 ODS. Genotyping of FTO gene rs17817449 polymorphism was performed using the restriction fragment length polymorphism (RFLP-PCR) method. Serum lipid and thyroid profiles were also assessed. The results revealed significant increase in the frequency of the FTO rs17817449 T allele among overweight /ODS children compared to NODS children (p=0.0099). Overweight/ODS children exhibited significantly higher frequencies of the FTO rs17817449 GT and TT genotypes compared to NODS children.

CONCLUSION

There is an association between FTO rs17817449 genetic variant and overweight/obesity among the studied DS groups. The FTO rs17817449 GT and TT genotypes, as well as TGs level, were identified as independent risk factors for predicting overweight and obesity in DS children.

WHAT IS KNOWN

• Overweight and obese-DS (ODS) children displayed higher BMI and atherogenic lipid profile than non-obese DS children (NODS). FTO gene polymorphism rs17817449 contributes to obesity development in general population, but there is conflicting information about the risk allele.

WHAT IS NEW

• FTO rs17817449 TT genotype and T allele were considered as independent risk factors for overweight and obesity development in DS children, so they could be used for obesity prediction in DS children.

Betaine and B12 Intake, Glutathione Concentration, and MTHFR, PEMT, and MTHFD1 Genotypes Are Associated with Diabetes-Related Parameters in Polish Adults

BACKGROUND

There is a growing body of evidence on associations between one-carbon metabolism (OCM) and diabetes-related parameters. For this reason, we aimed to examine the associations of plasma choline, betaine, trimethylamine N-oxide (TMAO), glutathione (GSH), serum folate, vitamin B12, dihydrofolate reductase (rs70991108) genotype, methylenetetrahydrofolate reductase (MTHFR) (rs180113) genotype, methylenetetrahydrofolate dehydrogenase (MTHFD1) (rs2236225) genotype, and phosphatidylethanolamine N-methyltransferase (rs7946 and rs12325817) genotype with fasting glucose level, insulin level, and diabetes-related indices.

METHODS

The study group consisted of 421 Polish adults aged 20-40 y. Food intake was assessed using a 3-d food diary. Plasma concentrations of choline, betaine, and TMAO were determined by ultra-high-performance liquid chromatography-electrospray ionization mass spectrometry. The total plasma GSH level was measured by high-performance liquid chromatography. Insulin, folate, and vitamin B12 concentrations were estimated by enzyme-linked immunosorbent assay method. Genotyping was performed with TaqMan probes.

RESULTS

GSH level was negatively associated with insulin (β = -0.11, P < 0.05) and gamma-glutamyl transferase (GGTP) (β = -0.12, P < 0.05), and positively associated with fasting glucose (β = 0.11, P < 0.05). Betaine intake was negatively associated with serum insulin concentration (β = -0.13, P < 0.05) and HOMA-IR (β = -0.12, P < 0.05). Choline intake was negatively associated with insulin (β = -0.17, P < 0.01). Serum folate level was negatively associated with GGTP (β = -0.11; P < 0.05). The methylenetetrahydrofolate reductase (MTHFR) CC genotype was associated with higher serum insulin levels (β = 0.15; P < 0.01) and higher HOMA-IR (β = 0.15, P < 0.01), whereas the MTHFD1 AA genotype was negatively associated with Quantitative Insulin Sensitivity Check Index (β = -0.11, P < 0.05).

CONCLUSIONS

Our findings suggest that higher GSHL and higher intake of betaine, B12, and choline, as well as the TT genotype of MTHFR and the AA genotype of MTHFD1, are associated with lower diabetes-related parameters among adults.

FTO gene variants (rs9939609, rs8050136 and rs17817449) and type 2 diabetes mellitus risk: A Meta-Analysis

BACKGROUND AND AIMS

There is tremendous increase in type 2 diabetes mellitus (T2DM) worldwide. The impact of FTO gene polymorphisms on the risk of T2DM is not yet clear because of the controversial results of studies. This meta-analysis aimed to better clarify the association between three FTO gene polymorphisms SNPs (rs9939609, rs8050136 and rs17817449) and T2DM in a larger combined population worldwide.

MATERIAL AND METHODS

A comprehensive search on the PubMed, Science Direct, and Web of Science databases was conducted to identify investigations in relationship between different FTO gene polymorphisms (rs9939609, rs8050136 and rs17817449) and T2DM globally. Published papers from January 2007 to May 2023 were collected. Inclusion criteria are limited to human case-control studies published in English and peer-reviewed, which provided data on the genotype distributions of FTO gene polymorphisms and T2DM risk. Odds ratios (OR) and 95% confidence intervals (CI) were calculated to express the results of the meta-analysis. Potential sources of bias and heterogeneity using Egger's regression analysis were also assessed.

RESULTS

Of 234695 identified articles, forty-eight studies were selected including 36,051 patients with T2DM and 51,266 control subjects. Overall, we found a significant increased risk of T2DM susceptibility and rs9939609 FTO gene polymorphism in the Allele contrast (A vs. T: OR = 1,30, 95% CI = 1.14; 1.48, P < 0,05, I2 = 0,94), Recessive model (AA vs. AT + TT: OR = 1,54, 95% CI = 1.19; 2.00, P < 0,05, I2 = 0,94), Dominant model (AA + AT vs. TT: OR = 1,26, 95% CI = 1.10; 1.45, P < 0,05, I2 = 0,89), homozygote model (AA vs. TT: OR = 1,60, 95% CI = 1.26; 2.03, P < 0,05, I2 = 0,90), and heterozygote model (AA vs. AT: OR = 1,43, 95% CI = 1.09; 1.88, P = 0,008, I2 = 0,93). we also found a significantly increased risk of T2DM susceptibility and rs8050136 FTO gene polymorphism under all models. For rs17817449 we did not find any association between with T2DM.

CONCLUSION

The present meta-analysis confirms that rs9939609 and rs8050136 in the FTO gene are significantly associated with T2DM, while rs17817449 does not show any association.

Complex Feline Disease Mapping Using a Dense Genotyping Array

The current feline genotyping array of 63 k single nucleotide polymorphisms has proven its utility for mapping within breeds, and its use has led to the identification of variants associated with Mendelian traits in purebred cats. However, compared to single gene disorders, association studies of complex diseases, especially with the inclusion of random bred cats with relatively low linkage disequilibrium, require a denser genotyping array and an increased sample size to provide statistically significant associations. Here, we undertook a multi-breed study of 1,122 cats, most of which were admitted and phenotyped for nine common complex feline diseases at the Cornell University Hospital for Animals. Using a proprietary 340 k single nucleotide polymorphism mapping array, we identified significant genome-wide associations with hyperthyroidism, diabetes mellitus, and eosinophilic keratoconjunctivitis. These results provide genomic locations for variant discovery and candidate gene screening for these important complex feline diseases, which are relevant not only to feline health, but also to the development of disease models for comparative studies.

Genetic polymorphisms associated with obesity in the Arab world: a systematic review

BACKGROUND

Obesity, one of the most common chronic health conditions worldwide, is a multifactorial disease caused by complex genetic and environmental interactions. Several association studies have revealed a considerable number of candidate loci for obesity; however, the genotype-phenotype correlations remain unclear. To date, no comprehensive systematic review has been conducted to investigate the genetic risk factors for obesity among Arabs.

OBJECTIVES

This study aimed to systematically review the genetic polymorphisms that are significantly associated with obesity in Arabs.

METHODS

We searched four literature databases (PubMed, Science Direct, Scopus, and Google Scholar) from inception until May 2020 to obtain all reported genetic data related to obesity in Arab populations. Quality assessment and data extraction were performed individually by three investigators.

RESULTS

In total, 59 studies comprising a total of 15,488 cases and 9,760 controls were included in the systematic review. A total of 76 variants located within or near 49 genes were reported to be significantly associated with obesity. Among the 76 variants, two were described as unique to Arabs, as they have not been previously reported in other populations, and 19 were reported to be distinctively associated with obesity in Arabs but not in non-Arab populations.

CONCLUSIONS

There appears to be a unique genetic and clinical susceptibility profile of obesity in Arab patients.

Genetic polymorphisms associated with type 2 diabetes in the Arab world: A systematic review and meta-analysis

AIMS

T2DM reach epidemic levels in the Arab countries. In this study, we aimed to perform a systematic review and meta-analysis to underline the susceptibility genetic profile of Arab patients with T2DM that result from SNPs.

METHODS

We searched four literature databases (PubMed, Scopus, Science Direct and Web of Science) through January 2019. We included all SNPs in candidate genes with an OR > 1 that were associated with T2DM among Arab patients with T2DM. Statistical programs such as software Review Manager (Version 5.02) and STATA (Version 15.1) were used. The pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated with a random effects model or a fixed effect model depending on the heterogeneity among studies. I² statistics and Egger's tests were performed to assess heterogeneity and publication bias.

RESULTS

Out of 2245 studies, 47 were used for meta-analysis. We captured 31,307 cases and 26,464 controls in which we collected 71 SNPs in 32 genes. A pooled meta-analysis demonstrated 24-69% increase in T2DM risk. Among the 57 SNPs (in 32 genes) that were not included in the meta-analysis, the OR for diabetes ranged from 1.02 to 5.10, with a median of 1.38 (interquartile range 1.33-2.09). Ten studies examined the association between the TCF7L2 polymorphism rs7903146 and T2DM, leading to an aggregated OR of 1.34 (95%CI 1.27-1.41).

CONCLUSION

The genetic profile that confer susceptibility to T2DM in Arab patients is diverse. This study may serve as a platform for designing a gene panel for testing the susceptibility to T2DM.