The CYLD syndrome encompasses three previously known appendageal tumor predisposition syndromes: familial cylindromatosis (FC, or Turban tumor syndrome; OMIM 132700), multiple familial trichoepithelioma 1 (MFT1; also called epithelioma adenoides cysticum, EAC, or Brooke-Fordyce trichoepitheliomas; OMIM 601606), and Brooke-Spiegler syndrome (BSS or BRSS; OMIM 605041), which are believed to be allelic disorders with overlapping phenotypes associated with CYLD mutations. Here, CYLD is linked to familial cylindromatosis.