The EGD examination of the third patient revealed small superficial ulcers over the infrapapillary region of the duodenum, and the biopsy revealed mucosal infiltrates of mononuclear cells with a positive NK cell phenotype (CD3+/CD45+/CD56+/TIA-1+), which was consistent with NK cell enteropathy. Here, NCAM1 is linked to NK-cell enteropathy.