Case Report: Severe periodontitis in adolescent monozygotic twins with ELANE-related neutropenia: a 42-month longitudinal observation

Background Neutrophils are central to innate immune defense in the periodontium, where they contribute to host protection at the gingival epithelial barrier and within the underlying periodontal tissues. Neutropenia may therefore present with severe periodontal inflammation and destruction early in life. This case report describes the diagnostic evaluation and 42-month periodontal course of 12-year-old monozygotic twin girls with severe periodontal disease who were subsequently found to have ELANE -related neutropenia. Case presentation Both patients initially showed generalized gingival erythema and edema, extensive attachment and alveolar bone loss, pathological tooth mobility, and bleeding on probing (BOP) at all examined sites. Persistent inflammation after initial non-surgical periodontal therapy (NSPT) prompted hematologic and genetic evaluation. Both twins had neutropenia and carried the same heterozygous ELANE variant, NM_001972.4:c.597 + 5G>T, previously reported in ELANE -related neutropenia. Because serial absolute neutrophil count (ANC) measurements sufficient to demonstrate periodic oscillation were unavailable, a cyclic phenotype could not be independently confirmed. During approximately 42 months of longitudinal periodontal care, sites with probing depth (PD) ≥7 mm decreased from 10% to 4% in Patient A and from 27% to 0% in Patient B, whereas BOP remained 100% in both patients at the final assessment. Conclusion Severe periodontal destruction in a child that is disproportionate to age and local risk factors should prompt consideration of an underlying hematologic or immune disorder. The concordant periodontal findings in monozygotic twins carrying the same ELANE variant provide a clinically informative familial observation, but do not establish a definitive genotype–phenotype relationship. Longitudinal PD reduction occurred during repeated periodontal care, but persistent generalized BOP indicated incomplete inflammatory control. These findings represent partial clinical improvement rather than definitive evidence of treatment efficacy and highlight the need for continued periodontal and hematological follow-up.