ARPC1B and dermatitis: In the frame of a study exploring RS in patients affected by CID, immune dysregulation, and/or severe dermatitis, before the identification of the SLC6A19 and ARPC1B gene mutations, we investigated DSB repair in irradiated fibroblasts from our PtII-1 index case, revealing an increased RS assessed by a higher fraction of γH2AX foci (Supplementary Figure S5).