Sertoli cell-only syndrome (SCO syndrome) is a cause of male infertility. In SCO syndrome, only Sertoli cells (cells that nurture the immature sperm) line the seminiferous tubules (tubes inside the testicles where sperm develop). Therefore, there are not any sperm cells present in the seminiferous tubules. Men typically learn they are affected between ages 20-40 years when being evaluated for infertility and are found to have no sperm production (azoospermia). Other signs and symptoms are rare, but in some cases there could be an underlying cause of SCO syndrome that causes other symptoms, such as Klinefelter syndrome.

Most cases of SCO syndrome are idiopathic (of unknown cause), but causes may include deletions of genetic information on regions of the Y-chromosome, especially on the azoospermia factor (AZF) region of Y-chromosome. Other causes include exposure to chemicals or toxins, history of radiation therapy, and history of severe trauma. Diagnosis of SCO syndrome is confirmed with testicular biopsy. Although there is currently no effective treatment, assisted reproductive technology may assist some men with SCO syndrome in being able to have children.

In some cases, SCO syndrome can be caused by another underlying disease. In these cases, it is possible for affected men to have other symptoms. For example, some men with SCO syndrome are later diagnosed with Klinefelter syndrome, another cause of male infertility. The signs and symptoms associated with underlying causes of SCO syndrome can vary.

If SCO syndrome is caused by a genetic change in a particular individual, it is unlikely that this change was inherited. This is because most genetic causes of SCO syndrome are caused by mutations of the Y chromosome. A male’s Y chromosome is inherited from his father, and men who have SCO syndrome are typically not able to have children unless they use specific reproductive technologies. Therefore, it would be unlikely for a person to have inherited the cause of SCO syndrome from his father. In some cases, though, a genetic change causing SCO syndrome may occur on another chromosome. In these cases, it is possible for SCO syndrome to run in families. More information about reproductive technologies that may allow a man with SCO syndrome to have children is included below.

Sertoli cell-only syndrome (SCO syndrome) is typically suspected in men who present with infertility despite having normal testosterone levels. Tests to confirm the diagnosis include a determination of azoospermia (no sperm production) and increased FSH (follicle-stimulating hormone) levels. The diagnosis is typically confirmed by a biopsy of the testicles showing no sperm production.

Unfortunately, success rate for this procedure may be limited. Current reports suggest that about 13% of men with SCO syndrome had successful procedures that resulted in having a child. Success of the procedure depends on the presence of any sperm cells in the testes, and many men with SCO syndrome may have complete absence of sperm cells. The success of the procedure may be better at centers that specialize in treating men with infertility, including men with SCO syndrome. In cases where TESE-ICSI is used, genetic testing is recommended beforehand for more information about whether or not the syndrome could be passed on to his children.

Men with SCO syndrome have been reported to have about a 10.5% risk to develop testicular cancer in their lifetimes. It is important to discuss this risk with your doctor and discuss methods of looking for testicular cancer such as clinical evaluations, ultrasonography, or MRI.