Gain-of-function variants in the KDF1 gene cause hidradenitis suppurativa associated with ectodermal dysplasia by stabilizing IκB kinase α.

Keratinocyte differentiation factor (KDF)1 has been shown to cause ectodermal dysplasia with or without hidradenitis suppurativa in a single family. KDF1 is known to regulate epidermal differentiation through its interaction with I kappa B kinase (IKK)alpha. We report a novel de novo KDF1 variant (p.His254Tyr) in a 20-year-old male patient presenting with hidradenitis suppurativa and ectodermal dysplasia. We demonstrate that variants in KDF1 associated with hidradenitis suppurativa actually cause pathogenic gain-of-function of KDF1 through upregulation of IKK alpha. Ectodermal dysplasia may be present in a subset of individuals with hidradenitis suppurativa and should be investigated. Inhibition of IKKa appears to be a suitable therapeutic target for these individuals.