Abstract
BackgroundGenetic causes of male infertility are hypothesized to involve multiple types of mutations, from single gene defects to complex chromosome rearrangements. Recently, several recurrent X-chromosome microdeletions (located in subtelomeric region of the long arm) were reported to be associated with male infertility in Spanish and Italian males. The aim of our study was to test their prevalence and infertility association in population of men from the Czech Republic.Methods107 males with pathological sperm evaluation resulting in nonobstructive infertility were compared to 131 males with normal fecundity. X-chromosome microdeletions were assessed by +/- PCR with three primer pairs for each region Xcnv64 (Xq27.3), Xcnv67 (Xq28) and Xcnv69 (Xq28). The latter microdeletion was further characterized by amplification across the deleted region, dividing the deletion into three types; A, B and C.ResultsWe detected presence of isolated Xcnv64 deletion in 3 patients and 14 controls, and Xcnv69 in 3 patients and 6 controls (1 and 1 patient vs.4 and 1 control for types A and B respectively). There was one control with combined Xcnv64 and Xcnv69 type B deletions, and one patient with combination of Xcnv64 and Xcnv69 type C deletions. The frequency of the deletions was thus not higher in patient compared to control group, Xcnv64 was marginally associated with controls (adjusted Fisher´s exact test P = 0.043), Xcnv69 was not associated (P = 0.452). We excluded presence of more extensive rearrangements in two subjects with combined Xcnv64 and Xcnv69 deletions. There was no Xcnv67 deletion in our cohort.ConclusionIn conclusion, the two previously reported X-linked microdeletions (Xcnv64 and Xcnv69) do not seem to confer a significant risk to impaired spermatogenesis in the Czech population. The potential clinical role of the previously reported patient-specific Xcnv67 remains to be determined in a larger study population.
Highlights
According to a global meta-analysis comprising 172413 women, 9% of couples are infertile worldwide [1]. Another recent metaanalysis estimated male infertility prevalence in Central and Eastern Europe to 8–12% [2] mainly based on data from Poland [3]
Substantial proportion of male infertility cases remain unexplained despite advances in clinical diagnostics; a large proportion of the latter is thought to be genetic in origin [4, 5]
Most common microdeletion Xcnv64 reached inverse association in our cohort. This cannot be taken as a final disproval of the association, since our study comprised 5.9x less subjects in the patient group compared to [14].Directly qualitatively comparing the sperm concentration of the patients with the microdeletions Xcnv64 and Xcnv69 there were 13 subjects with azoospermia (13/163, i. e. 7.9%), 40 subjects with low sperm concentration (40/463, i.e. 8.6%) and 5 subjects with normal sperm concentration in the South European cohort; in our study there was one subject with azoospermia (1/23, i.e. 4.3%), 4 subjects with oligozoospermia
Summary
According to a global meta-analysis comprising 172413 women, 9% (i.e. about 70 million) of couples are infertile worldwide [1]. Another recent metaanalysis estimated male infertility prevalence in Central and Eastern Europe to 8–12% [2] mainly based on data from Poland [3]. Most prevalent genetic cause of male infertility is Klinefelter syndrome, about 4% in unselected infertile males [6, 7] and the azoospermia factor (AZF) deletions in the male specific region of the Y chromosome, ranging from 4% in oligospermic males to 11% in azoospermic males [8].
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