Netherton syndrome (Online Mendelian Inheritance in Man No. 256500 [http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=256500]) is a rare, autosomal recessive genetic disorder characterized by infantile erythroderma, a chronic eczematous dermatitis, ichthyosis linearis circumflexa, sparse brittle hair with hair-shaft abnormalities (trichorrhexis invaginata), variable immunologic defects, and failure to thrive. Recent genetic studies in patients with Netherton syndrome have identified mutations in the SPINK5 gene, which encodes the serine protease inhibitor Kazal type 5,1 that are thought to result in impaired epidermal barrier function, increased transepidermal water loss, increased susceptibility to infection, and increased permeability to exogenous agents.
Shah KN, Yan AC. Low But Detectable Serum Levels of Tacrolimus Seen With the Use of Very Dilute, Extemporaneously Compounded Formulations of Tacrolimus Ointment in the Treatment of Patients With Netherton Syndrome. Arch Dermatol. 2006;142(10):1361-1375. doi:10.1001/archderm.142.10.1362