Why doest the result wire become a vertex?

I got three TopoDS_Edges ,they can be combined into a triangle.
It looks like no problem.
But I do not get a triangle wire,I get a vertex instead.
Why this happened?
What's the problem with the process?
Please make me clear,thank you.
Below is the code

const TopoDS_Edge edge1st = TopoDS::Edge(Tools::readShapeFromBRep("D:/share/extendedSecondEdge[0].brep"));
const TopoDS_Edge edge2nd = TopoDS::Edge(Tools::readShapeFromBRep("D:/share/extendedSecondEdgenextEdge[0].brep"));
const TopoDS_Edge edge3rd = TopoDS::Edge(Tools::readShapeFromBRep("D:/share/extendedSecondEdgepreEdge[0].brep"));
BRepBuilderAPI_MakeWire wireMaker;
TopTools_ListOfShape edgeList;
edgeList.Append(edge1st);
edgeList.Append(edge2nd);
edgeList.Append(edge3rd);
wireMaker.Add(edgeList);
Tools::writeShapeToBRep(wireMaker.Wire(), "D:/share/resultDebugWire.brep");