Is there a possible correlation between chromosomal variants and spermatogenesis?
OBJECTIVE
Heterochromatin polymorphism is considered a variant of a normal karyotype but is more frequent in infertile men. The aim of this study was to evaluate the correlation between heterochromatic variants and male infertility and to discuss the possible mechanisms of how heterochromatic polymorphism might affect spermatogenesis.


METHODS
Cytogenetic analysis was undertaken in 210 infertile males who had been taken into assisted reproductive techniques and in 183 men with proven fertility. Additionally, C-banding was performed in men with heterochromatin polymorphism. Sperm fluorescence in situ hybridization (FISH) was applied in 54 men with normal karyotype presenting either normal or abnormal sperm parameters as well as in 8 men with heterochromatin polymorphism. The outcomes of assisted reproductive techniques were compared between infertile men with normal karyotype and men with heterochromatin polymorphism.


RESULTS
The incidence of heterochromatin polymorphism was higher in infertile men. The most frequent chromosome involved in heterochromatin polymorphism was chromosome 9. Sperm FISH analysis revealed an increased rate of aneuploidy in men with heterochromatin polymorphism. Laboratory and clinical outcomes in assisted reproductive techniques were compromised in men with heterochromatin polymorphism.


CONCLUSIONS
An increased rate of heterochromatin polymorphism in infertile males seems to be more than an incidental finding, and must not be considered as a normal variant. Polymorphic heterochromatin may have deleterious effects on the genetic constitution of spermatozoa. More attention must be directed to infertile men with heterochromatin polymorphism.
Yakin
Kayhan
K
Assisted Reproduction Unit, American Hospital of Istanbul, Istanbul, Turkey. kayhany@amerikanhastanesi.com.tr
Balaban
Basak
B
Urman
Bulent
B
D000328:Adult; D000782:Aneuploidy; D002872:Chromosome Deletion; D041322:Chromosomes, Human, Y; D020732:Cytogenetic Analysis; D005260:Female; D006570:Heterochromatin / Q000235:genetics*; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007248:Infertility, Male / Q000235:genetics*; D008297:Male; D011110:Polymorphism, Genetic; D027724:Reproductive Techniques, Assisted; D013091:Spermatogenesis / Q000235:genetics*; D013094:Spermatozoa / Q000502:physiology
D006570:Heterochromatin