- Impaired glucagon-like peptide-1-induced insulin secretion in carriers of transcription factor 7-like 2 (TCF7L2) gene polymorphisms. Schäfer, S.A., Tschritter, O., Machicao, F., Thamer, C., Stefan, N., Gallwitz, B., Holst, J.J., Dekker, J.M., 't Hart, L.M., t'Hart, L.M., Nijpels, G., van Haeften, T.W., Häring, H.U., Fritsche, A. Diabetologia (2007)