ABSTRACT
We aimed to investigate the relationship between HLA alleles in patients with type 1 diabetes from an admixed population and the reported race/skin color of their relatives. This cross-sectional, multicenter study was conducted in public clinics in nine Brazilian cities and included 662 patients with type 1 diabetes and their relatives. Demographic data for patients and information on the race/skin color and birthplace of their relatives were obtained. Typing of the HLA-DRB1, -DQA1, and -DQB1 genes was performed. Most studied patients reported having a White relative (95.17%), and the most frequently observed allele among them was DRB1*03:01. Increased odds of presenting this allele were found only in those patients who reported having all White relatives. Considering that most of the patients reported having a White relative and that the most frequent observed allele was DRB1*03:01 (probably a European-derived allele), regardless of the race/skin color of their relatives, we conclude that the type 1 diabetes genotype comes probably from European, Caucasian ethnicity. However, future studies with other ancestry markers are needed to fill the knowledge gap regarding the genetic origin of the type 1 diabetes genotype in admixed populations such as the Brazilian.
Subject(s)
Diabetes Mellitus, Type 1 , HLA-DQ Antigens , Brazil/epidemiology , Cross-Sectional Studies , Diabetes Mellitus, Type 1/epidemiology , Diabetes Mellitus, Type 1/genetics , Genotype , HLA-DQ Antigens/genetics , HLA-DQ alpha-Chains/genetics , HLA-DQ beta-Chains/genetics , HLA-DRB1 Chains/genetics , Humans , Skin Pigmentation/geneticsABSTRACT
OBJECTIVE: To determine the influence of genomic ancestry (GA) and self-reportedcolor-race (SRCR) on glycemic control in adolescents with type 1 diabetes (T1D) in an admixed population. RESEARCH DESIGN AND METHODS: This multicenter nationwide study was conducted in 14 public clinics in 10 Brazilian cities. We estimated global and individual African, European, and Native Amerindian GA proportions using a panel of 46 AIM-INDEL markers. From 1760 patients, 367 were adolescents (20.9%): 184 female (50.1%), aged 16.4 ± 1.9 years, age at diagnosis 8.9 ± 4.3 years, duration of diabetes 8.1 ± 4.3 years, years of study 10.9 ± 2.5 and HbA1c of 9.6 ± 2.4%. RESULTS: Patients SRCR as White: 176 (48.0%), Brown: 159 (43.3%), Black: 19(5.2%), Asians: 5 (1.4%) and Amerindians: 8 (2.2%). The percentage of European GA prevailed in all groups: White (71.1), Brown (58.8), Black (49.6), Amerindians (46.1), and Asians (60.5). Univariate correlation was noted between A1c and African GA, r = 0.11, P = .03; years of study, r = -0.12 P = .010, and having both private and public health care insurance (r = -0.20, P < .001). After adjustments, the multivariate logistic analysis showed that SRCR or GA did not influence glycemic control. CONCLUSIONS: A high percentage of European GA was noted in our patients, even in those who self-reported as non-White, confirming the highly admixed ethnicity of the Brazilian population. Better glycemic control was associated with having both types of health care; however, there was no association between glycemic control with GA or SRCR. Future prospective studies with other admixed populations are necessary to confirm our findings.