Familial cylindromatosis is a rare dominantly inherited disease characterized by 
the development of multiple benign tumours of the skin appendages, including 
cylindromas, trichoepitheliomas and spiradenomas. The gene responsible was 
positionally cloned recently, and was designated CYLD. We describe a family with 
cylindromatosis, in which affected individuals have an inherited R758X nonsense 
mutation of CYLD. Affected members of this family manifest a relatively mild 
tumour phenotype; the largest tumour was only 30 mm in diameter. Thus far, there 
is no evident genotype-phenotype relationship in cylindromatosis, although the 
number of families reported with both phenotypic and genotypic data remains 
small.