Somatic variants are variations in an individual’s genome acquired after the zygotic stadium and result from mitotic errors or not (fully) repaired DNA damage.
To investigate whether somatic mosaicism in T lymphocyte subsets is enriched early in multiple sclerosis (MS).
We identified somatic variants with variant allele fractions ≥1% across the whole exome in CD4+ and CD8+ T lymphocytes of 21 treatment-naive MS patients with <5 years of disease duration and 16 partially age-matched healthy controls. We investigated the known somatic
All subjects carried 1-142 variants in CD4+ or CD8+ T lymphocytes. Variants were more common, more abundant, and increased with age in CD8+ T lymphocytes. Somatic variants were common in the genes
Somatic variation in T lymphocyte subsets is widespread in both control individuals and MS patients. Somatic mosaicism in T lymphocyte subsets is not enriched in early MS and thus unlikely to contribute to MS risk, but future research needs to address whether a subset of variants influences disease susceptibility.