Is the CAG repeat of mitochondrial DNA polymerase gamma (POLG) associated with male infertility? A multi-centre French study.
BACKGROUND
Recent data emphasized the implication of polymerase gamma (POLG) CAG repeats in infertility, making it a very attractive gene for study. A comparison of POLG CAG repeats in infertile and fertile men showed a clear association between the absence of the usual 10-CAG allele and male infertility, excluding azoospermia. It has also been suggested that the POLG gene polymorphism should be considered as a possible contributing factor in unexplained couple infertility where semen parameters are normal. In this study, we investigated the POLG CAG repeats, in a well-defined population of patients with severe male factor infertility.


METHODS
We conducted a large study of POLG CAG repeats in 433 infertile and 91 fertile, normozoospermic and healthy males. In all subjects, phenotypic data, including semen parameters, hormonal status and clinical profiles, were available.


RESULTS
Thirteen 'homozygous mutants' (3%) were found among the 433 idiopathic infertile patients. The follow-up of the 13 'homozygous mutant' resulted in pregnancy for more than half of the couples, through assisted reproductive techniques or even spontaneously. In addition, one 'homozygous mutant' was identified in 91 fertile men (1.1%)


CONCLUSIONS
Under our conditions, our study does not confirm any relationship between the polymorphic CAG repeat in the POLG gene and male infertility.
Aknin-Seifer
I E
IE
Laboratoire de Biologie de la Reproduction, Service de Génétique Moléculaire, CHU-Hôpital Nord, Saint Etienne, France.
Touraine
R L
RL
Lejeune
H
H
Jimenez
C
C
Chouteau
J
J
Siffroi
J P
JP
McElreavey
K
K
Bienvenu
T
T
Patrat
C
C
Levy
R
R
D000328:Adult; D016022:Case-Control Studies; D000074002:DNA Polymerase gamma; D004272:DNA, Mitochondrial / Q000235:genetics*; D004259:DNA-Directed DNA Polymerase / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D006720:Homozygote; D006801:Humans; D007248:Infertility, Male / Q000235:genetics* / Q000503:physiopathology / Q000628:therapy; D008297:Male; D009154:Mutation; D011247:Pregnancy; D018873:Pregnancy Rate; D027724:Reproductive Techniques, Assisted; D012720:Severity of Illness Index; D018911:Trinucleotide Repeats
D004272:DNA, Mitochondrial; D000074002:DNA Polymerase gamma; D004259:DNA-Directed DNA Polymerase