The genetic and cytogenetic basis of male infertility

Abstract

Despite the difficulties in determining the relative maternal vs. paternal contributions to infertility it is often suggested that a male factor problem is implicated in 50% of cases. This review is concerned specifically with male fertility disorders that have a clearly defined genetic component. The genetic causes of infertility can be broken down into Y chromosome deletions (specifically deletions in the AZF a, b, and c regions), single gene disorders (particularly those relating to the CFTR gene), multifactorial causes and chromosome abnormalities. Chromosome abnormalities can be numerical (such as trisomy--full blown or mosaic) or structural (such as inversions or translocations). Of especial interest at present is the incidence of levels of numerical chromosome abnormalities in the sperm of infertile men; prospects for screening sperm for such abnormalities are discussed.

Genetic anomalies in patients with severe oligozoospermia and azoospermia in eastern Turkey: a prospective study

“…Male factor is assumed to be responsible in about 50% of the infertile couples. Not only defects in hormone production, testicular structure, ejaculation and/or the spermatozoa themselves can adversely affect the chances of conception, but also genetic defects can affect the fertility (Griffin and Finch, 2005). The incidence of chromosome abnormalities is about ten times higher in infertile men than in the general population.…”

“…Infertility is usually described as the inability of a couple to conceive after one year of unprotected intercourse (Griffin and Finch, 2005). Infertility is a major health problem today affecting about 10-20% of couples (Mittal et al, 2004).…”

The Genetics of Male Infertility: A Field of Study Whose Time Is Now

“…Some genes are likely to limit spermatogenesis, hence causing azoospermia or severe oligozoospermia. Alternatively, genes involved in spermiogenesis may alter sperm functional ability by affecting such processes as capacitation, the acrosome reaction, and pronuclear function [1,6,7,9,19]. Initial studies indicate that polymorphisms in such genes may be associated with human male infertility.…”

“…Other relevant gene mutations include mutations to the CFTR gene, which can lead to congenital bilateral absence of the vas deferens (CBAVD), and genes associated with cryptorchidism [26]. Additionally, numerical chromosome anomalies, such as Klinefelter's syndrome (XXY) or XX males with an SRY translocation, would be included in developmental errors potentially resulting in male infertility [7,17]. During fetal development, the primordial germ cells (PGCs) must physically migrate from the yolk sac to the genital ridge and undergo a proliferation phase.…”

“…The genetic causes of infertility are currently a major emphasis of both basic and clinically applied research studies [6,7,15,17]. The range of topics and the breadth of specialists involved in these studies are broad and expanding.…”