Patients' characteristics. (A) Pedigree for patient 2 with TTC7A deficiency. (B) Integrative Genomics Viewer of whole exome sequencing data from patient 2. Broad gray bars represent sequenced reads aligned to the reference genome. Thin gray bars represent missing/deleted segments (large 34-bp deletion demonstrated in exon 1, confirmed on Sanger sequencing). (C) Hematoxylin and eosin–stained gut biopsies taken pre-HSCT and 6 months and 18 months post-HSCT (from left to right) from patient 2. Unfilled white arrows indicate apoptotic debris. Filled white arrows indicate infiltration of the lamina propria with lymphocytes, eosinophils, plasma cells, and neutrophils. (D) Position of all causative mutations within TTC7A gene (top line: exon 1-20) and position within TTC7A protein (lower line: tetratricopeptide repeat domains 1-9) for all 4 patients.