- Mutations in the protein kinase A R1alpha regulatory subunit cause familial cardiac myxomas and Carney complex. Casey, M., Vaughan, C.J., He, J., Hatcher, C.J., Winter, J.M., Weremowicz, S., Montgomery, K., Kucherlapati, R., Morton, C.C., Basson, C.T. J. Clin. Invest. (2000)