PSEN1 and Epidermal Inclusion Cyst: Mutations were identified in the genes of the γ-secretase, genes of the NOTCH pathway, PSENEN (presenilin-enhancing gamma-secretase subunit), PSEN1 (presenilin 1), NCSTN (nicastrin), when γ-secretase function is impaired in mice, follicular keratinization, follicular atrophy, epidermal cyst formation, absence of sebaceous glands, and epidermal hyperplasia occur, features that can also be found in HS [12,13].