A U wave as seen on ECG. An electrocardiogram of an 18-year-old man showing U waves, most evident in lead V3. The U wave is a wave on an electrocardiogram that is not always seen. It is typically small, and, by definition, follows the T wave. U waves are thought to represent repolarization of the papillary muscles or Purkinje fibers.
HCP is caused by mutations in the CPOX gene, which codes for the enzyme coproporphyrinogen oxidase. This enzyme is responsible for the sixth step in the heme biosynthetic pathway, converting coproporphyrinogen III to protoporphyrinogen IX.
The most common hereditary disorder of hemostasis is von Willebrand disease (see Von Willebrand Disease) The most common hereditary coagulation disorders are the hemophilias. NOTE: This is the Professional Version. NOTE: This is the Professional Version. Abnormal bleeding can result from disorders of the coagulation system (see Overview of Hemostasis), of platelets, or of blood vessels. Disorders of coagulation can be acquired or hereditary.