<p>(A) Hematoxylin and Eosin stained intestinal biopsy; epithelial compartment is labeled. (B) Adjacent tissue section to that from panel A stained for X- (green) and Y- (red) chromosomes and Lamin B1 (white). Arrows indicate Y-chromosome-positive epithelial cells and the arrowhead points to a Y-chromosome-positive non-epithelial cell. Inset shows a sub-region stained for cytokeratin (blue); arrows and arrowhead serve as positional references. (C) Enlarged views of cells indicated in panel B by arrows and arrowhead; sex-karyotype is indicated for each. (D) Independent patient sample also stained for X- (green) and Y- (red) chromosomes and Lamin B1 (white). Arrows indicate Y-chromosome-positive epithelial cells. Dashed lines in all panels indicate boundaries of epithelial and non-epithelial compartments.</p