Dyskeratosis congenita - The severe infant-onset form of this disease (Hoyeraal-Hreidarsson syndrome) presents with enteropathy, IUGR, failure to thrive, cerebellar hypoplasia, and combined immunodeficiency. GI biopsies may reveal the presence of epithelial cell apoptosis identical to gut GVHD.
IPEX - Patients develop intractable chronic diarrhea secondary to autoimmune small bowel inflammation (the colon can also be affected). Biopsy of the bowel reveals villous atrophy and lymphocytic infiltrates in the mucosa. Apoptosis of GI tract epithelial cells resembling gut GVHD can also be described.