Primary pigmented nodular adrenocortical disease (PPNAD) is a genetic disorder usually associated with Carney complex, a syndrome of multiple endocrine gland abnormalities caused by inactivating germline mutations of the PRKAR1A gene, leading to constitutive activation of the cAMP–PKA pathway by increasing the availability of the PKA catalytic subunits [121]. This evidence concerns the gene PRKAR1A and primary pigmented nodular adrenocortical disease.