This study aims to contribute to ongoing research concerning how MKT isconstituted at mathematics teacher education. The Learning Study (LS)presented in this paper focused on Mathematical Knowledge for Teaching(MKT) amongst student teachers (ST). The data consists of three videotapedseminars and pre and post tests written by ST. Analysis with Variation theory(VT) resulted in a description of critical features to take into account whenteaching MKT to at teacher education. In this paper the critical feature related to the curriculum is explored