Study of the Huntington's disease <i><scp>IT</scp>‐15</i> gene in different ethnic groups in Ecuador

<jats:p>This study aims to establish the current state of the <jats:italic><jats:styled-content style="fixed-case">IT</jats:styled-content>‐15</jats:italic> (<jats:italic><jats:styled-content style="fixed-case">HTT</jats:styled-content></jats:italic>) gene in different Ecuadorian ethnic groups and patients by determining <jats:styled-content style="fixed-case">CAG</jats:styled-content> triplet repeats, compared with the ethnicity of individuals. A total of 412 individuals were studied using nested polymerase chain reaction and Sanger sequencing: 75 individuals were indigenous (Kichwas), 211 mestizos, and 65 Afro‐Ecuadorians. We included 31 patients who were clinically diagnosed with Huntington's disease (HD) and relatives of the affected patients (<jats:italic>n</jats:italic> = 30). Moreover, we correlated the presence of HD in Ecuadorian patients with 46 genetic ancestry‐informative insertion‐deletion polymorphic markers. We found that 77.20% had <28 <jats:styled-content style="fixed-case">CAG</jats:styled-content> repetitions, 18.80% had mutable alleles, 2.27% had incomplete penetrance, and 1.70% reflected >39 repetitions. The average of <jats:styled-content style="fixed-case">CAG</jats:styled-content> repetitions was 24 ± 3 for indigenous people; 28 ± 2 for mestizos; and 24 ± 3.2 repetitions for the Afro‐Ecuadorians. The ancestral component showed that the main ancestry corresponded to Native Americans (0.873) and European ascendants (0.145), Africans were less represented in the evaluated population (0.018). There was a significant difference between the number of <jats:styled-content style="fixed-case">CAG</jats:styled-content> repeats in mestizos and indigenous people (<jats:italic>P</jats:italic> < .01), suggesting that the Ecuadorian mestizo population has a risk factor for the gene mutation.</jats:p>