- A homozygous mutation in HESX1 is associated with evolving hypopituitarism due to impaired repressor-corepressor interaction. Carvalho, L.R., Woods, K.S., Mendonca, B.B., Marcal, N., Zamparini, A.L., Stifani, S., Brickman, J.M., Arnhold, I.J., Dattani, M.T. J. Clin. Invest. (2003)