The other genes involved in the pathogenesis of AD at the level of the epidermal barrier are genes encoding a serine protease inhibitor (SPINK-5 / LEKT1, cystatin A), genes encoding epidermal proteases: mast cell chymase gene (CMA1), epidermal chymotrypsin and trypsin gene, epidermal N-methyltransferase gene (responsible for the degradation of histamine) [23,34]. The gene discussed is CMA1; the disease is Alzheimer disease.