Resolving a genetic paradox throughout preimplantation genetic diagnosis for autosomal dominant severe congenital neutropenia.
OBJECTIVE
Severe congenital neutropenia is an inherited disease characterized by low peripheral blood neutrophils, amenable to bone marrow transplantation. Genetic analysis in the family here described detected a ELA2 splice-site mutation in the affected child and also in his asymptomatic father. The parents requested preimplantation genetic diagnosis (PGD), coupled with HLA matching, to obtain a suitable bone marrow donor for the affected child.


METHODS
A PGD protocol was developed, based on multiplex nested PCR for direct analysis of the ELA2 mutation, flanking polymorphic markers and HLA typing.


RESULTS
The amplification efficiency of the mutation was > 90% in single leukocytes from the affected child but only 67% in the father. Analysis of single haploid sperm cells from the father demonstrated three different sperm-cell populations: (1) sperm cells harboring the ELA2 mutation on the 'affected' haplotype, (2) sperm cells without the ELA2 mutation on the 'normal' haplotype, and (3) sperm cells without the ELA2 mutation on the 'affected' haplotype.


CONCLUSIONS
These data demonstrate that the ELA2 mutation in the father occurred de novo during his embryonic development, resulting in somatic as well as germ-line mosaicism. This conclusion was also taken into consideration when PGD was performed.
Malcov
Mira
M
Sara Racine in vitro Fertilization Unit, Lis Maternity Hospital, Tel Aviv, Israel.
Reches
Adi
A
Ben-Yosef
Dalit
D
Cohen
Tania
T
Amit
Ami
A
Dgany
Orly
O
Tamary
Hannah
H
Yaron
Yuval
Y
D004252:DNA Mutational Analysis; D000075065:Elongin; D005192:Family Health; D005220:Fathers; D005260:Female; D005307:Fertilization in Vitro; D005799:Genes, Dominant; D006580:Genetic Carrier Screening; D020022:Genetic Predisposition to Disease; D006801:Humans; D007958:Leukocyte Count; D008297:Male; D009154:Mutation; D009503:Neutropenia / Q000151:congenital* / Q000235:genetics*; D009504:Neutrophils / Q000473:pathology; D010375:Pedigree; D019836:Preimplantation Diagnosis / Q000379:methods*; D022821:RNA Splice Sites / Q000235:genetics; D013094:Spermatozoa / Q000737:chemistry; D014157:Transcription Factors / Q000235:genetics
D000075065:Elongin; D022821:RNA Splice Sites; D014157:Transcription Factors