case_images: PMC10701422_01
case_images: Gut investigations and molecular characterization. (A) Endoscopic images revealed two polyploid lesions of the left colon with underlying stricture of lumen which prevented further progression of the endoscope. (B) Histology showed chronic active colitis with rarefaction and distortion of the glandular crypts and heavy diffuse inflammatory infiltrate, including lymphocytes (CD4+++, CD8-), plasma cells, neutrophils, and eosinophils in the lamina propria with crypt abscesses. Goblet cell depletion; no granulomas or giant cell reaction were present. (C) WES results featuring mutations found in DUOX2 and genealogical tree showing hereditary pattern of disease.
case_images: fgene-14-1276697-g001.jpg
case_images: PMC10701422_01_fgene-14-1276697-g001.jpg
case_images: F1
case_images: Left colonic sigma and rectum mucosa was fragile, with multiple erosions of mild intensity (Figure 1A). Histological examination of surgical colonic samples showed chronic active colitis, with rarefaction and distortion of the glandular crypts and heavy diffuse inflammatory infiltrate, including lymphocytes (CD4+++, CD8-), plasma cells, neutrophils, and eosinophils in the lamina propria with crypt abscesses (Figure 1B). Two different variants in DUOX2 (NM_014080) were found: the c.2524C>T mutation inherited from her father and the c.3175C>T variant inherited from her mother (Figure 1C).
case_images: Functional characterization of DUOX2 mutation R1059C. (A) H202 generation by DUOX2 WT and DUOX2 R1059C in H661-DUOXA2 cells; stimulation with PMA (10Ong/m1) and thapsigargin (1 kM); empty vector served as negative control. Error bars +/- standard deviation (n = 9); Brown-Forsythe and Welch one-way ANOVA with Dunnett's T3 post hoc test **I3 5 0.005. (B) Expression of HA-DUOX2 WT and HA-DUOX2 R1059C in H661- DUOXA2 cells; vinculin and actin served as loading controls. (C) Immunofluorescence microscopy of DUOX2 (red) stained biopsy sections from a healthy donor and the patient confirming apical membrane localization; DAPI for nuclei (blue) (scale bar 50F.tm).
case_images: fgene-14-1276697-g002.jpg
case_images: PMC10701422_01_fgene-14-1276697-g002.jpg
case_images: F2
case_images: Expression of mutant DUOX2 was altered, and stimulated H2O2 generation was significantly decreased (10%-15%) when compared to wildtype DUOX2 (Figures 2A,B). Immunofluorescence microscopy of patient tissue samples revealed DUOX2 expression at the apical side of the intestinal epithelium, indicating that DUOX2 expression and translocation was preserved, albeit that available antibodies may also detect truncated DUOX2 if the protein remains stably expressed (Figure 2C).