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.
Related to Lupus. Genetic Markers Spotted for Lupus. Nov. 10, 2006 -- New research on the genetic roots of lupus may eventually lead to a blood test to help diagnose the disease. Lupus is an autoimmune disease in which the immune system mistakes the body's connective tissue for a foreign invader and attacks it. The exact cause of lupus isn't known, but research suggests a mix of genetic and environmental influences.