Based on human MUC4 organization, we designed primer sets to analyze the possible expression of Muc4 variants in 4‐week‐old KC mice (Figure S8C, Supporting Information), and found that duct‐like cells express more Muc4, including Muc4/X and Muc4/Y, than acinar cells (Figure S8D, Supporting Information). The gene discussed is MUC4; the disease is keratoconus.