Preferential location of sex chromosomes, their aneuploidy in human sperm, and their role in determining sex chromosome aneuploidy in embryos after ICSI.
BACKGROUND
In babies born after ICSI procedures, an increase of de-novo sex chromosome abnormalities has been observed. Several hypotheses have been proposed to explain these findings: an increased rate of sex chromosome aneuploidy in sperm of oligozoospermic men, or a preferential location of the sex chromosomes in the sub-acrosomal region of the sperm nucleus which leads to a reduced DNA decondensation of this region. In order to investigate which theory may be more reliable, we studied the localization of sex chromosomes and their aneuploidy rate in sperm in men undergoing ICSI.


METHODS
Using fluorescent in-situ hybridization we studied sex chromosome localization and the aneuploidy rate for sex chromosomes and chromosome 18 in 20 oligospermic men undergoing ICSI and in 10 controls.


RESULTS
In 40.94 and 52.92% of cases, the X and Y chromosomes respectively were localized in the sub-acrosomal region of the sperm nucleus compared with only 14.29% of cases of chromosome 18 (P < 0.001). An increase of sex chromosome aneuploidy in sperm of oligospermic men was observed; 2.91 versus 0.69% of controls (P < 0.001).


CONCLUSIONS
Sex chromosomes are localized preferentially in the sub-acrosomal region of sperm and sex chromosome aneuploidy rate in the sperm of oligozoospermic men is higher than in controls.
Sbracia
M
M
Centro di Endocrinologia e Medicina della Riproduzione, Università 'La Sapienza' Rome, Italy. marcandrea@hotmail.com
Baldi
M
M
Cao
D
D
Sandrelli
A
A
Chiandetti
A
A
Poverini
R
R
Aragona
C
C
D000177:Acrosome / Q000648:ultrastructure; D000328:Adult; D000782:Aneuploidy; D002467:Cell Nucleus / Q000648:ultrastructure*; D002887:Chromosomes, Human, Pair 18 / Q000235:genetics; D002890:Chromosomes, Human, Pair 20 / Q000235:genetics; D004622:Embryo, Mammalian / Q000502:physiology*; D006801:Humans; D008297:Male; D009845:Oligospermia / Q000235:genetics*; D012016:Reference Values; D012730:Sex Chromosomes / Q000235:genetics* / Q000648:ultrastructure*; D020554:Sperm Injections, Intracytoplasmic; D013094:Spermatozoa / Q000648:ultrastructure*