Supplementary Figure 1: Proliferation of SASH1 fibroblasts and control fibroblasts was in the same range (mean of 3 controls) (1). Thus the difference in favor of SASH1 fibroblasts in the wound-healing assay may be due to cell migration and not cell proliferation. SASH1 mRNA expression quantified by RT-qPCR in the fibroblast of the patient was the same as control (2). Cell survival assays showing normal sensitivity of patient's fibroblasts to ionizing radiations at 0, 2 and 6 grays (3) and to UVC radiation at 0, 7.5 and 15 J/m2 as compared with wild type AS405 control fibroblasts (4). Experiments were done in triplicate. Standard deviations are shown. Supplementary Table 1: Homozygous regions identified by genome-wide homozygosity mapping Proximal recombinant SNP Distal recombinant SNP chr4:179110516_185338506 6 227 rs2378811 rs17488206 chr6:108312267_110669620 2 357 rs2008860 rs7770648 chr6:131373431_152446057 21 072 rs954211 rs2747653 chr8:3688710_22643323 18 954 rs9650512 rs11991347 chr8:26078324_27796020 1 717 rs4376504 rs2685309 chr8:33410077_35558646 2 148 rs7845367 rs6998842 chr20:16654521_39513502 22 858 rs4239719 rs4142345 Interval (hg19) Size (Mb) 1