PLCD1 and Pilar Cysts

Trichilemmal or pilar cysts are commonly found on the scalp and are derived from the outer root sheath of the hair follicle. Multiple trichilemmal cysts present in an autosomal dominant pattern of inheritance, yet the genetic mechanism has remained elusive. In this issue, Horer et al. (2019) highlight predisposing variants in PLCD1 in such families and propose a monoallelic mutational mechanism that drives cyst formation.