Ebtesam

Hi, Im a medical student and was studying pathology when I came across the genetic mutations associated with pituitary adenomas. Amongst the mutations was a gain-of-function mutation of the Protein Kinase A, regulatory subunit 1 (PRKAR1A) gene. I am confused as to how a gain-of-function mutation of the PRKAR1A gene leads to unregulated cAMP activity as PRKAR1A encodes a negative regulator of Protein Kinase A. So, shouldn't a gain-of-function mutation lead to supressed activity of Protein Kinase A?