Developing a core outcome set for Netherton syndrome: An international multi-stakeholder e-Delphi consensus study

Netherton syndrome (NS; OMIM#256500) is a rare and severe disorder of epidermal maturation and keratinization caused by pathogenic variants in the serine protease inhibitor Kazal type 5 (SPINK5), leading to severe skin barrier impairment. Although effective treatment is crucial for NS patients, there is a lack of knowledge on what the best treatment options are for these patients. Large heterogeneity in reported outcomes and measurement instruments hinders accurate comparison of treatment results across studies and the development of a treatment guideline. Therefore, we aimed to develop a core outcome set (COS) for NS that can be used in clinical care and research.