Novel ELANE Mutation Associated with a Clinical Presentation of Cyclic Neutropenia

Congenital neutropenia, defined by absolute neutrophil count (ANC) 2.5x109/L in infants, includes a variety of genotypic alterations that manifest with chronic immunodeficiency and, as a result, presents in infancy with recurrent infections. The gene that encodes neutrophil elastase, ELANE, has pathological variants yielding two distinct phenotypes: severe congenital neutropenia (SCN) and cyclic neutropenia (CyN). While SCN exhibits persistent pathologic ANC values, CyN exhibits pathologic ANC values in a patterned fashion which can recur in 21-day intervals. Here, we describe a patient with a novel heterozygous ELANE deletion (c.224+(4_19)del16) presenting with clinical features consistent with CyN and a response to first-line therapy of granulocyte colony- stimulating factor.