Pre-testicular Causes

 Pre-testicular (not obstructive) causes: Poor sex hormone production prevents testicles from producing sperm. This can be caused by Kallmann Syndrome: a genetic (inherited) disorder that is transmitted to the X chromosome and is characterized by low levels of gonadotropin-releasing hormone (GnRH) and loss of odour. GnRH stimulates the pituitary gland to secrete hormones that control the reproductive system. Factors that influence the regulation of normal testicular hormones are obesity, low testosterone levels, drugs, steroids, drugs. Pre-testicular factors are associated with conditions that inhibit adequate testicular support and include situations with poor hormonal support and poor overall health, including varicoceles, a condition of testicular swelling. Recently there has been increasing evidence of abnormal sperm DNA methylation associated with abnormal sperm parameters and male infertility. Common variants inherited in genes that encode enzymes used to correct DNA incompatibility are associated with an increased risk of DNA damage and sperm infertility in men. As a man ages, sperm quality continues to decline, and this decrease seems to be caused by DNA damage.  

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