PRKAR1A and neoplasm: The R1α subunit inhibits PKA function, and PRKAR1A mutations originate a truncated protein that is functionally null, thus leading to increased intracellular signaling via PKA, and consequent endocrinal hyperactivity or tumor formation.4-6 In most other families, mutations of the 2p16 locus have been found, thus suggesting their involvement in the pathogenesis of the disease.4,7,8