A lentiviral construct containing Gnas with an arginine to cysteine change at codon 201 (R201C) under the constitutive human phosphoglycerate kinase promoter were used to generate mice. and an EGFP under the CMV promoter were used to generate mice. No information is provided about EGFP expression. Two founders were established: 60 and 61. Line 60 is entered as a representative line.