The point where Utah, Colorado, New Mexico, and Arizona meet is called  Four Corners and is unique among the states. Arizona base map, Courtesy of Maps.com. This elevation map of Arizona illustrates the number of feet or meters the state rises above sea level. The lowest areas of the state are along the Colorado River where a low point of 70 feet above sea level is reached. The highest point in Arizona is in the northern part of the state.
The exact cause of Barrett's esophagus is not known. It may result from damage to the esophagus caused by the chronic reflux of stomach acid. Frequent or chronic reflux of stomach acid into the esophagus is called gastroesophageal reflux disease or GERD. Gastroesophageal Reflux.
Prader-Willi syndrome is caused by the loss of function of genes in a particular region of chromosome 15. People normally inherit one copy of this chromosome from each parent.