diff --git a/gtsam/linear/NoiseModel.h b/gtsam/linear/NoiseModel.h
index 04c26336f..7d95d9276 100644
--- a/gtsam/linear/NoiseModel.h
+++ b/gtsam/linear/NoiseModel.h
@@ -870,6 +870,7 @@ namespace gtsam {
   typedef noiseModel::Gaussian::shared_ptr SharedGaussian;
   typedef noiseModel::Diagonal::shared_ptr SharedDiagonal;
   typedef noiseModel::Constrained::shared_ptr SharedConstrained;
+  typedef noiseModel::Isotropic::shared_ptr SharedIsotropic;
 
 } // namespace gtsam