Genetic and Childhood Sperm Disorders
Many causes of male infertility are thought to be due to genetics. With the human DNA sequence completed, more conditions of male infertility caused by genetics have been discovered. Some known genetic causes of problems with male fertility include:
- Klinefelter syndrome: There are two sex X chromosomes in addition to the Y (XXY).
- Kallmann syndrome: Pituitary production of luteinizing hormone and follicle stimulating hormone is low or absent.
- Kartagener syndrome, primary ciliary dyskinesia or immotile cilia syndrome: These all cause structural problems in the microscopic tubes in the sperm tail.
- Congenital bilateral absence of the vas deferens (CBAVD): Changes in the gene responsible for cystic fibrosis cause the vas deferens to be absent.
- Androgen insensitivity syndrome: The receptor that binds to testosterone is altered.
- 5-a-reductase deficiency: The enzyme that converts testosterone to the more active form dihydrotestosterone is altered.
- Persistent Müllerian duct syndrome: Female organs develop in the male embryo.
- Changes in the deleted in azoospermia (DAZ) gene: Alterations in a gene on the Y chromosome interfere with sperm production.
Sperm production is inactive until puberty. If the testis does not descend in the scrotum (a condition called cryptorchidism), early sperm cells may be permanently damaged. Early treatment of cryptorchidism by surgery to bring the testis into the scrotum, called orchidopexy, is important to preserve a male’s later fertility. Other childhood conditions that may affect future fertility include:
- mumps orchitis: mumps involving the testis,
- testis torsion: the testis twists on itself, and
- testis trauma: injury significant enough to disrupt the inside of the testis.
Hormonal and Immune System Sperm Disorders
Failure of the pituitary to release luteinizing hormone (LH) and follicle stimulating hormone (FSH) causes failure of the testis to produce testosterone and sperm. This condition is diagnosed by low testosterone accompanied by relatively low LH levels. The most extreme example of pituitary failure is Kallmann syndrome, which may be treated with human chorionic gonadotropin (hCG) and recombinant FSH, often requiring treatment periods of a year or more. Milder forms of pituitary problems are common and may be treated with clomiphene citrate if the pituitary is responsive.
Failure of the Leydig cells in the testis to make testosterone results in low levels of testosterone accompanied by very high levels of LH as the negative feedback of testosterone on the pituitary is decreased. Treatment is surgical extraction of sperm if possible, as the body is already providing its own hormonal stimulation.
Testosterone therapy is not used as a treatment for male fertility.
High levels of the hormone estradiol may impair male fertility; this condition can be treated with medications such as anastrozole (Arimidex). High levels of sex hormone binding globulin may also lower the amount of effective testosterone, referred to as “bioavailable” testosterone. If the total or bioavailable testosterone is too low, clomiphene citrate may be used to increase the production of testosterone in the testes.
White blood cells in the semen release toxic chemicals that may affect sperm function. Antioxidants, antibiotics and anti-inflammatory medication may help prevent sperm damage by excessive white blood cells in the semen.