Hidradenitis suppurativa (HS) is a debilitating chronic inflammatory skin condition of unclear etiology. It may segregate as an autosomal dominant trait, and heterozygous mutations in the γ-secretase genes NCSTN, PSENEN, and PSEN1 have recently been reported in a small number of multiplex kindreds and sporadic cases. These mutations highlight γ-secretase (an enzyme that has been extensively investigated in familial Alzheimer's disease) to have an integral role in cutaneous biology and, more specifically, in HS. In this article, we review the recent genetic data, how they inform disease pathogenesis, and the long-term implications in HS and related diseases.