Overlapping Xp21.2 duplications define an X-linked hypotrichosis simplex and implicate TAB3 dosage sensitivity

Overlapping Xp21.2 duplications define a previously unrecognized X-linked hypotrichosis simplex driven by increased TAB3 dosage. Functional studies demonstrate that TAB3 overexpression perturbs TAK1-NF-κB signaling, induces inflammatory skin abnormalities, and disrupts hair follicle homeostasis, highlighting pathogenic copy-number variation as a mechanism underlying hereditary hair disorders.