Gain of Function Mutations of PIK3CD as a Cause of Primary Sclerosing Cholangitis.

Gain of function (GOF) mutation in the p110δ catalytic subunit of the phosphatidylinositol-3-OH kinase (PIK3CD) is the cause of a primary immunodeficiency (PID) characterized by recurrent sinopulmonary infections and lymphoproliferation. We describe a family of two adults and three children with GOF mutation in PIK3CD, all with recurrent sinopulmonary infections and varied infectious and non-infectious complications. The two adults have Primary Sclerosing Cholangitis (PSC) without evidence of Cryptosporidium parvum infection and have required liver transplantation. PSC is a novel phenotype of GOF mutation in PIK3CD.