While P1 showed increased pS6 levels both in CD4+ and CD8+ T cells upon in vitro activation, P1’s mother harboring the same PIK3CD variant did not exhibit signs of PI3K hyperactivation, suggesting that the former maybe due to external factors such as recent or ongoing viral infection or similar (Supplementary Figures 1B, C). The gene discussed is PIK3CD; the disease is viral infectious disease.