Cyclic Neutropenia
Cyclic neutropenia is a rare genetic disorder characterized by recurrent episodes of low neutrophil counts, leading to periodic infections and inflammation that resolve when white blood cell levels return to normal.
Overview
Cyclic neutropenia is a disorder that causes frequent infections and other health problems in affected individuals. People with this condition experience recurrent episodes of neutropenia, a shortage (deficiency) of neutrophils. Neutrophils are a type of white blood cell that plays a critical role in inflammation and fighting infection.
These episodes of neutropenia are apparent at birth or soon afterward. For most affected individuals, neutropenia recurs every 21 days and lasts about 3 to 5 days. Because neutropenia makes it more difficult for the body to fight off pathogens such as bacteria and viruses, people with cyclic neutropenia typically develop recurrent infections. However, these health problems occur only during episodes of neutropenia. At times when neutrophil levels are normal, individuals are not at an increased risk of infection and inflammation.
Symptoms
During episodes of neutropenia, affected individuals may experience a variety of symptoms, including:
- Recurrent infections of the sinuses, respiratory tract, and skin
- Open sores (ulcers) in the mouth and colon
- Inflammation of the throat (pharyngitis) and gums (gingivitis)
- Recurrent fever
- Abdominal pain
Causes & Risk Factors
Genetic Cause
Mutations in the ELANE gene cause cyclic neutropenia. The ELANE gene provides instructions for making a protein called neutrophil elastase, which is found in neutrophils. When the body starts an immune response to fight an infection, neutrophils release neutrophil elastase. This protein modifies the function of certain cells and proteins to help fight the infection.
Mutations in the ELANE gene lead to an abnormal neutrophil elastase protein that retains some of its function. However, neutrophils that produce this abnormal protein appear to have a shorter lifespan than normal neutrophils. This shorter lifespan is thought to be responsible for the cyclic nature of the condition. When affected neutrophils die early, there is a period of shortage because it takes time for the body to replenish its supply.
Inheritance
Cyclic neutropenia is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In most cases, an affected person inherits the mutation from an affected parent. Other cases result from new mutations in the gene and occur in people with no history of the disorder in their family.
Frequency
Cyclic neutropenia is a rare condition, estimated to occur in 1 in 1 million individuals worldwide.
Other Names
- Cyclic hematopoesis
- Cyclic leucopenia
- Periodic neutropenia