A case report of de novo ELANE c.416C>T mutation causing cyclic neutropenia in a 7-year-old girl.

OBJECTIVE

Childhood cyclic neutropenia (CN) is a rare hematopoietic disorder. We describe the clinical phenotype, diagnostic features, and management of a pediatric CN case caused by a de novo ELANE mutation, to improve clinical recognition and care.

METHODS

We retrospectively analyzed clinical, laboratory, and genetic data from a 7-year-old girl with CN, combined with bioinformatics and literature review to explore genotype-phenotype correlations and optimal therapy.

RESULTS

The patient presented with classic 21-day cyclic episodes of fever, oral ulcers, and lymphadenopathy. Peripheral blood absolute neutrophil count (ANC) fell to 0.04×109/L at nadir, accompanied by monocytosis. Whole-exome sequencing identified a de novo heterozygous ELANE c.416C>T (p.Pro139Leu) variant. The Pro139 residue is highly conserved across species, and substitution is predicted to impair neutrophil elastase structure and function. The patient responded well to recombinant human granulocyte colony-stimulating factor (rhG-CSF) plus infection control and supportive care and is currently awaiting hematopoietic stem cell transplantation (HSCT).

CONCLUSION

Pediatric CN features periodic fever and mucosal infection. Diagnosis requires both cyclic neutropenia documented by serial monitoring and pathogenic ELANE variant confirmation. rhG-CSF remains first-line therapy. Identification of this de novo c.416C>T variant broadens the genotypic spectrum of ELANE-related CN. Early and accurate diagnosis, individualized treatment, and long-term follow-up are critical to improve outcomes.