Our clinical-laboratory experience is that patients with lesions that clinically suggest DH and have a positive serological test result for IgA antibodies to tTG, but an initial negative reading of the traditional DIF specimen, cutting the DIF specimen further, and reexamining it for IgA DH-type deposits can yield a positive result. This evidence concerns the gene TGM2 and dermatitis herpetiformis, familial.