Genetic disorders and male infertility

Abstract

Background: At present, one out of six couples is infertile, and in 50% of cases, infertility is attributed to male infertility factors. Genetic abnormalities are found in 10%-20% of patients showing severe spermatogenesis disorders, including non-obstructive azoospermia.

Methods: Literatures covering the relationship between male infertility and genetic disorders or chromosomal abnormalities were studied and summarized.

Main findings results: Genetic disorders, including Klinefelter syndrome, balanced reciprocal translocation, Robertsonian translocation, structural abnormalities in Y chromosome, XX male, azoospermic factor (AZF) deletions, and congenital bilateral absence of vas deferens were summarized and discussed from a practical point of view. Among them, understanding on AZF deletions significantly changed owing to advanced elucidation of their pathogenesis. Due to its technical progress, AZF deletion test can reveal their delicate variations and predict the condition of spermatogenesis. Thirty-nine candidate genes possibly responsible for azoospermia have been identified in the last 10 years owing to the advances in genome sequencing technologies.

Conclusion: Genetic testing for chromosomes and AZF deletions should be examined in cases of severe oligozoospermia and azoospermia. Genetic counseling should be offered before and after genetic testing.

Keywords: Klinefelter syndrome; azoospermia; genetic disorder; male infertility; sex chromosome aberrations.

FIGURE 1

Scheme of deletion patterns of AZF region based on palindromes in Y chromosome long arm. The STS primers suggested by guidelines (sY85, sY86, sY127, sY134, sY254, sY255) are also located. In addition to AZF deletions (AZFa, AZFb, AZFb+c, AZFc), partial deletions (b1/b3, b2/b3, gr/gr) are indicated by arrows