Genome-wide association study identifies novel type II diabetes risk loci in Jordan subpopulations.

The prevalence of Type II Diabetes (T2D) has been increasing and has become a disease of significant public health burden in Jordan. None of the previous genome-wide association studies (GWAS) have specifically investigated the Middle East populations. The Circassian and Chechen communities in Jordan represent unique populations that are genetically distinct from the Arab population and other populations in the Caucasus. Prevalence of T2D is very high in both the Circassian and Chechen communities in Jordan despite low obesity prevalence. We conducted GWAS on T2D in these two populations and further performed meta-analysis of the results. We identified a novel T2D locus at chr20p12.2 at genome-wide significance (rs6134031, P = 1.12 × 10-8) and we replicated the results in the Wellcome Trust Case Control Consortium (WTCCC) dataset. Another locus at chr12q24.31 is associated with T2D at suggestive significance level (top SNP rs4758690, P = 4.20 × 10-5) and it is a robust eQTL for the gene, MLXIP (P = 1.10 × 10-14), and is significantly associated with methylation level in MLXIP, the functions of which involves cellular glucose response. Therefore, in this first GWAS of T2D in Jordan subpopulations, we identified novel and unique susceptibility loci which may help inform the genetic underpinnings of T2D in other populations.

Nutrient intake and lifestyle factors by diabetes status of Circassians and Chechans in Jordan.

OBJECTIVES: Diabetes is one of the most prevalent diseases in Jordan. However, little is known about nutrient intakes of minority groups in Jordan with and without diabetes. Our study aimed to examine if the intake of energy, macronutrients and some micronutrients differed between normal and diabetic adults among Circassians and Chechans in Jordan. DESIGN, SETTING, PARTICIPANTS: This cross-sectional study was conducted among 437 Circassians (160 males and 277 females) and 355 Chechans (119 males and 236 females) aged > or = 18 years. They were recruited from the Chechan and Circassian communities living in Jordan. MAIN OUTCOME MEASURES: A participant was defined as affected by type 2 diabetes mellitus if diagnosis was known to patient or if his or her condition complied with the American Diabetes Association definition. One 24-hour dietary recall for each participant was collected by face-to-face interview. RESULTS: Most of the measured anthropometric and biochemical parameters showed a significant difference between normal individuals and those with impaired fasting glucose or diabetes. Intakes of nutrients involved in the pathogenesis of diabetes including protein, fat and fiber did not differ between stratified participants according to blood glucose status for both Circassians and Chechans. CONCLUSIONS: Intake of nutrients did not differ in participants with normal blood glucose from those who had impaired fasting glucose or diabetes in the two studied populations. These two populations may need genetic studies to identify the risk factors other than dietary and lifestyle factors for type 2 diabetes.

Prevalence of coagulation factor II G20210A and factor V G1691A Leiden polymorphisms in Chechans, a genetically isolated population in Jordan.

BACKGROUND: Coagulation factor II G20210A and coagulation factor V (Leiden) G1691A single nucleotide polymorphisms (SNPs) are major inherited risk factors of venous thromboembolism. In view of the heterogeneity in their world distribution and lack of sufficient information about their distribution among Chechans, we addressed the prevalence of these SNPs in the Chechan population in Jordan, a genetically isolated population. METHODS AND RESULTS: Factor II G20210A and factor V Leiden SNPs were analysed by polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) method and Amplification refractory mutation detection system (ARMS) respectively in 120 random unrelated subjects from the Chechan population in Jordan. Among the subjects studied for factor II G20210A mutation there were three individuals carrying this mutation as heterozygous (one female and two male), giving a prevalence of 2.5 % and an allele frequency of 1.25 %. No homozygous factor II allele was found. Factor V Leiden G1691A mutation was detected as heterozygous in 22 of 120 of individuals (17 female and five male) indicating a prevalence of 18.3 % and allele frequency of 9.2 %. No homozygous allele was found. CONCLUSION: Our results indicated that prevalence of factor II G20210A mutation in the Chechan population is similar to prevalence in Jordan and Caucasian populations (1-6 %) while the prevalence of factor V Leiden was higher in the Chechan population compared to Jordan and Caucasian populations (2-15 %).

Diabetes mellitus in genetically isolated populations in Jordan: prevalence, awareness, glycemic control, and associated factors.

OBJECTIVES: Diabetes mellitus is one of the most common non-communicable diseases globally. This study seeks to estimate the prevalence of impaired fasting glycemia and type 2 diabetes mellitus in genetically isolated populations in Jordan: the Circassians and Chechans. RESEARCH DESIGN AND METHODS: Data were analyzed from a cross-sectional study that included a random sample of adult Circassians and Chechans. A subject was defined as affected by diabetes mellitus if diagnosis was known to patient or, according to the American Diabetes Association definition. Impaired fasting glucose was defined as a fasting serum glucose level of ≥6.1 mmol/L (100 mg/dl) but <7 mmol/L. HbA(1c) >7% was defined as 'unsatisfactory' metabolic control. RESULTS: The prevalence of impaired fasting glycemia was 18.5% for Circassians and 14.6% for Chechans. Prevalence of diabetes was 9.6% for Circassians and 10.1% for Chechans. The prevalence of impaired fasting glycemia and diabetes were significantly higher in men, older age groups, married, subjects of lower educational level, past smokers, and subjects with obesity. Low high-density lipoprotein cholesterol was the most common abnormality in the two populations. CONCLUSIONS: The homogenous, genetically isolated Circassian and Chechan populations sharing the same environmental influences suggest a role for genetic risk factors for diabetes. Thus these two populations are suitable for additional genetics studies that may lead to the identification of novel risk factors for type 2 diabetes. In addition, more than half of patients with diabetes were with unsatisfactory control. Therefore, they are likely to benefit from programs encouraging healthy weight and physical activity.