Prekallikrein Deficiency, also known as fletcher factor deficiency, is related to pyruvate kinase deficiency of red cells and factor xii deficiency. An important gene associated with Prekallikrein Deficiency is KLKB1 (Kallikrein B1), and among its related pathways/superpathways are Response to elevated platelet cytosolic Ca2+ and Collagen chain trimerization. Affiliated tissues include heart and b cells, and related phenotypes are prolonged partial thromboplastin time and reduced circulating prekallikrein concentration