Familial benign chronic pemphigus (FBCP) is an uncommon hereditary acantholytic disorder transmitted as an irregular autosomal dominant trait. The lesions appear primarily on flexural skin areas, but the disease also exists in a latent form in normal appearing skin. Latent acantholysis can be made manifest by subjecting the normal appearing skin to various noxious stimuli. The demonstration that ultraviolet light can easily induce this acantholytic phenomenon in patients with FBCP prompted the study of a family with this disease in an effort to identify clinically normal "carriers" of the gene. Two members in the family were discovered by means of a simple phototest method, which appears not only to identify the clinically normal heterozygote of FBCP but also to be useful in the diagnosis of suspected disease in remission when clinical lesions are not apparent.
Cram DL, Muller SA, Winkelmann RK. Ultraviolet-Induced Acantholysis in Familial Benign Chronic PemphigusDetection of the Forme Fruste. Arch Dermatol. 1967;96(6):636-641. doi:10.1001/archderm.1967.01610060030003