SMAD4 and cholesteryl ester measurement: Although the similarities shared among Smad4kera-cko, Tgfbr2kera-cko, and CE patients indicate the involvement of SMAD4-dependent signaling in the CE-like pathogenesis, the pathological appearance in the keratocyte of Tgfbr2kera-cko mice might result from the SMAD4-independent signaling pathway.