Figure 1. Identification and characterization of RFWD3 mutation.

(A) WES data reveal 2 heterozygous sequence variants in the RFWD3 gene, highlighted in green. The gene is located on the minus strand; chromosomal and amino acid positions next to the mutations are depicted atop the sequence data. (B) Sanger sequencing confirms both mutations in individual 1143 and familial segregation. (C) Histograms reflecting proportions of cells with the indicated number of chromosomal breaks per metaphase, blue without, red after exposure to mitomycin C (MMC). Dashed lines delimit high rates (>7) of RFWD3-mutated (1143) and unproductively transduced fibroblasts (1143+mock, 1143+I630K). Rates of 1143+WT are rescued. Fifty metaphases each were scored. The 1143 plot is reused in Supplemental Figure 1B. (D–G) Dose-response curves of the same cell lines used in C compared with non-FA and FA control (FA-Q, FA-B, or FA-D1) fibroblasts after exposure to the indicated agents and concentrations. The data represent mean ± SEM; N = 5. The 1143 and non-FA curves of D are reused in Figure 2E. The 1143 and non-FA curves of F are reused in Supplemental Figure 2G.