PURPOSE: Three familial cases of each of severe congenital neutropenia (SCN) and 
cyclic neutropenia (CN) in addition to 3 sporadic cases of SCN were analyzed for 
neutrophil elastase (Ela2) gene mutation. The contents of the 
neutrophil-specific granule proteins cathelicidin antimicrobial peptide and 
neutrophil gelatinase-associated lipocalin were also analyzed in SCN.
METHODS: Genomic DNA was extracted from the patients' peripheral blood or bone 
marrow, and the coding sequence of the Ela2 gene was amplified by polymerase 
chain reaction and subjected to direct sequencing. The contents of antimicrobial 
peptides were analyzed by flow cytometry.
RESULTS: Three cases of familial SCN (P13L, R52P, and S97L), 2 of familial CN 
(W212stop and P110L), and 1 of sporadic SCN (V72M) were shown to have 
heterozygous mutations in the Ela2 gene. W212stop found in a familial CN case 
was a novel mutation of Ela2. Prophylactic treatment for growth factors or 
antibiotic prophylaxis against bacterial infection was useful for lowering the 
frequency of infectious episodes. Adult patients tended to have less frequent 
infections compared with minors in the same family. The contents of both 
cathelicidin antimicrobial peptide and neutrophil gelatinase-associated 
lipocalin were significantly reduced in SCN compared with healthy controls.
CONCLUSIONS: Prophylaxis by growth factor or antibiotics is useful for 
decreasing risks of bacterial infections in SCN and CN. Adults were likely to 
have less frequent infections than children in familial cases of SCN and CN with 
the same mutation of Ela2.