Definition: Microcnemia is a condition characterized by a low level of oxygen in the blood. This can occur due to a variety of reasons, such as genetic defects or certain medical conditions. In some cases, it may also be caused by a lack of oxygen-carrying cells in the lungs, which are responsible for carrying oxygen throughout the body. Microcnemia is often seen in people who have a genetic mutation that affects their ability to produce enough red blood cells, or in individuals with certain medical conditions