Investigation of the P1104A/TYK2 Genetic Variant in a COVID-19 Patient Cohort from Southern Brazil

The P1104A variant in the TYK2 gene is recognized as the first common monogenic cause of tuberculosis, and recent studies also suggest a potential role in COVID-19 severity. However, its frequency and impact in admixed Latin American populations remain underexplored. Therefore, we investigated the P1104A/TYK2 variant in a cohort comprising 1826 RT-PCR-confirmed COVID-19 patients from Southern Brazil. Cases were stratified by severity into non-severe (n = 1190) and severe (n = 636). Three homozygous individuals were identified—one non-severe and two severe cases—although no statistically significant association with disease severity was observed. The frequency of the C allele in the COVID-19 cohort (2.85%) was significantly higher than in Brazilian population databases, including “DNA do Brasil” (1.81%, p < 0.001) and ABraOM (2.34%, p = 0.03), but lower than in the multi-ancestry gnomAD database (3.71%, p = 0.01), possibly reflecting ancestry bias. We also observed associations between COVID-19 severity and sex (p = 0.003), age (p < 0.001), obesity (p < 0.001), diabetes (p < 0.001), and hypertension (p < 0.001). Future studies in larger and more diverse cohorts are needed to characterize the prevalence of the variant in admixed populations and assess its contribution to COVID-19 susceptibility.