BACKGROUND: Cyclic neutropenia (CN) and severe congenital neutropenia (SCN) are 
disorders of neutrophil production that differ markedly in disease severity. 
Mutations of the ELANE gene (the symbol recently replacing ELA2) are considered 
largely responsible for most cases of CN and SCN, but specific mutations are 
typically associated with one or the other.
PROCEDURE: We performed ELANE genotyping on all individuals and paternal sperm 
in an SCN kindred with eight SCN progeny of a sperm donor and six different 
mothers.
RESULTS: One patient with CN had the same S97L ELANE mutation as seven patients 
with the SCN phenotype. The mutant allele was detected in the donor's 
spermatozoa, representing 18% of the ELANE gene pool, but not in DNA from his 
lymphocytes, neutrophils, or buccal mucosa, indicating gonadal mosaicism.
CONCLUSIONS: The coexistence of CN and SCN phenotypes in this kindred with a 
shared paternal haplotype strongly suggests both a role for modifying genes in 
determination of congenital neutropenia disease phenotypes, and the 
classification of CN and SCN within a spectrum of phenotypes expressing varying 
degrees of the same disease process.