Thymus‐derived Tregs maintain central immune tolerance and are generated in response to intermediate/high‐affinity interactions with self‐antigens,48, 49 as well as after UVB exposure.50 Elevated numbers of thymus‐derived Tregs have been detected in the circulation of AD patients51 and in the skin‐draining lymph nodes of mice exhibiting AD‐like symptoms.18 Here, we showed that the proportion of circulating thymus‐derived Tregs is higher in AD patients heterozygous for a FLG null mutation than in AD patients without a FLG null mutation. The gene discussed is FLG; the disease is Alzheimer disease.