CBLN1 and Alzheimer disease: As we show in this report, it is noteworthy that the Cer [NP]/[NS] ratio not only discriminates normal and non-lesional skin of patients with AD, but also shows a significant correlation with SC functional parameters both in barrier-disrupted skin and in healthy skin, which suggests that the Cer [NP]/[NS] ratio could be a potential marker to evaluate skin conditions even in healthy skin.