P-336: Mitochondrial haplogroups in individuals with type 1 diabetes mellitus in Brazil and Portugal
L Ferreira, I Adiala, R Azulay, S do Vale, M Duarte, E Oliveira, A Turchetto-Zolet, D Silva, M Brito GomesAbstract
Introduction
Type 1 diabetes (T1D) is a chronic autoimmune disease influenced by genetic, environmental, and immunological factors. Portugal has a higher incidence of T1D than Brazil. While Portugal has a homogeneous population predominantly of European ancestry, Brazil is characterized by extensive genetic admixture. Analysis of mitochondrial DNA (mtDNA) provides valuable insights into disease susceptibility, particularly in admixed populations.
Objectives
The aim of this study was to evaluate mitochondrial haplogroups in individuals with T1D from Brazil and Portugal.
Methods
Demographic and clinical data were collected using questionnaires. The mtDNA control region was sequenced, haplotypes were defined by comparison with the Revised Cambridge Reference Sequence (rCRS), and haplogroups were assigned using the EMPOP platform. Statistical analyses were performed using R (v4.5.2) and Arlequin software.
Results
Foram observadas distribuições distintas de haplogrupos mitocondriais entre os dois países, com maior diversidade de linhagens no Brasil e maior homogeneidade em Portugal. O Brasil apresentou maior frequência de haplogrupos nativos americanos e africanos, enquanto Portugal exibiu predominância de haplogrupos europeus. A AMOVA revelou uma estrutura genética forte e significativa do mtDNA entre os grupos (Norte + Nordeste, Sul + Sudeste e Portugal). A análise FST corrobora esse padrão. Em contrapartida, a diferenciação genética dentro dos grupos foi baixa e não significativa (0,0054), indicando compartilhamento de haplótipos que reflete a história demográfica dessas regiões.
Conclusions
These findings support the existence of distinct genetic patterns among individuals with T1D from Brazil and Portugal, reflecting their different demographic histories. Brazil exhibited greater haplotypic diversity, whereas Portugal showed higher genetic homogeneity despite the shared historical origins of the two countries.