Elastase 2: Neutrophil elastase, an enzyme in neutrophils that digests elastin. The gene ELA2 encoding elastase 2 is on chromosome 19p13,3. Mutations in ELA2 cause cyclic neutropenia, a blood disease in which there are regular cyclic fluctuations in the numbers of neutrophils and other blood cells. The cycles are classically 21 days but may range from 15 to 35 days. Patients with the disease typically have regularly recurring symptoms of fever, malaise, mucosal ulcers, and are at risk for life-threatening infections during periods of neutropenia.