A Case Report of Netherton Syndrome: A Significant Increase in Blood Tacrolims Level after a Clinical Trial of 0.1% Topical Tacrolims

Abstract

Netherton syndrome is a congenital ichthyosis associated with variable erythroderma, hair shaft defects, and atopic features. Mutations in the SPINK5 gene encoding the serine protease inhibitor LEKIT (lymphoepithelial Kazal-type related inhibitor) have been found in Netherton syndrome. These mutations cause over-desquamation of corneocytes, high skin permeability, and barrier dysfunction. A 6-year old girl diagnosed with atopic dermatitis under went a clinical trial of 0.1% tacrolims ointment, which was applied twice daily. However, her blood tacrolims concentration increased significantly. Because the girl was suspected to have Netherton syndrome, her corneum trypsin-like hydrolytic activity was examined and found to be approximately twice as high as those of controls. A mutation of the SPINK5 gene was identified. Based on these results, the girl was diagnosed as Netherton syndrome.