High frequency of mitochondrial haplogroups H and H2 in medieval individuals from the Cathedral of Santa María (Basque Country). Their contribution to the study of inflammatory arthropathies

Abstract

The haplogroup H has been associated with high mitochondrial energy efficiency, which may have favoured survival and reproduction under adverse environmental conditions. On the other hand, it enhances the production of Reactive Oxygen Species (ROS), which are involved in the pathogenesis of several arthropathies, especially those of inflammatory origin (IAs). In the present study, we analysed mtDNA haplogroups H and H2 in a sample composed of 55 individuals recovered from the Cathedral of Santa María (Basque Country, 12th-18th centuries) including both individuals with arthropathies (N = 31) and a control group (N = 24). The obtained results showed a particularly high frequency of haplogroup H (64.5%) compared with other present and ancient populations from Northern Spain. This frequency was higher (83.3%) in individuals with Inflammatory Arthropathies (IAs). A relevant relationship was found between sub-haplogroup H2 and Spondyloarthropathies (SpAs), which is a type of Inflammatory Arthropathy (IA) that affects the axial skeleton. This relationship indicates that the H2 individuals present a greater tendency toward developing SpAs, which allows suggesting the influence of this sub-haplogroup on the etiopathogenesis of this type of diseases. The present study demonstrates that the application of a simple and straightforward methodology of aDNA analysis can be used to improve the knowledge on ancient populations, in this case the dwellers of Vitoria-Gasteiz during the Middle Ages. This approach requires taking into account the historical context, due to its important influence on the health of the population, especially when considering pathologies with a strong environmental background, such as IAs.