Study of in Vivo and in Vitro Transcriptomic and Proteomic Signatures in Unhereditary Ichtyosis

Inclusion Criteria: * Aged 15-80 years old * Having an ARCI or EI, confirmed by a molecular diagnosis of a mutation in at least one of the following genes: TGM1, ALOX12B, NIPAL4, ABCA12, keratin 1 and keratin 10) * Having stopped all topical treatments in at least 1% of the total body surface (equivalent to one palm of the hand of the patient), at least 8 days before the skin biopsy (which will be performed on this untreated area). * Patients having a molecular diagnostic of genetic ichtyosis * No contraindication to skin biopsy * Health insurance coverage * Signature of written consent Exclusion Criteria: * Aged less than 15 of over 80 years old * Ichtyosis without a molecular confirmed diagnosis or with a different diagnosis * History, in the 8 previous days, of any topical treatment on the area intended for the skin biopsy. * No health insurance coverage * Pregnant or breastfeeding woman * Patient under guardianship or curatorship * Patient under State Medical Assistance (AME)