Disorders of Sperm Function or Motility

A. Immotile Cilia Syndromes

Immotile cilia syndromes are a heterogeneous group of disorders (1:20,000 males) in which sperm motility is reduced or absent. The sperm defects are due to abnormalities in the motor apparatus or axoneme of sperm and other ciliated cells. Normally, 9 pairs of microtubules are organized around a central pair within the sperm tail and are connected by dynein arms (ATPase) that regulate microtubule and therefore sperm tail motion. Various defects in the dynein arms cause deficits in ciliary and sperm activity. Kartagener syndrome is a subset of this disorder (1:40,000 males) that presents with the triad of chronic sinusitis, bronchiectasis, and situs inversus. Most immotile cilia cases are diagnosed in childhood with respiratory and sinus difficulties. Cilia present in the retina and ear may also be defective and lead to retinitis pigmentosa and deafness in Usher syndrome. Men with immotile cilia characteristically have nonmotile but viable sperm in normal numbers. Sperm nuclear material is thought to be unaffected. The diagnosis is made with electron microscopy of sperm.

B. Maturation Defects

After vasectomy reversal, normal sperm counts but low motility is often observed. This is thought to be due to elevated epididymal intratubular pressure and epididymal dysfunction, a consequence of time after vasectomy-induced blockage. As a result, sperm may not gain the usual maturation and motility capacities during transit through the epididymis.

C. Immunologic Infertility

Autoimmune infertility has been implicated as a cause of infertility in 10% of infertile couples. The testis is a curious organ in that sperm are highly antigenic, yet normally coexist within the host; it is an immunologically privileged site, probably owing to the blood-testis barrier, which consists of Sertoli cell tight junctions and locally downregulated cellular immunity. Autoimmune infertility may result from an abnormal exposure to sperm antigens after, for example, vasectomy, testis torsion, or biopsy, which then incites a pathologic immune response.

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