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development. Alterations in these mechanisms are essential events in the phys-
iopathology of some sperm-related fertilization failures.
2.2 Sperm Pathologies in Infertile Men with
Special Reference to Those Related
to Centrioles and Centrosomes
Teratozoospermia has been reported as an important cause of male infertility. Two
main forms of sperm anomalies can be identified in teratozoospermia (Chemes
2000
). The first and more frequent variety consists of heterogeneous combinations
of sperm anomalies randomly distributed in different patients. These alterations are
referred to as non-specific or non-systematic sperm anomalies. They are usually
secondary to andrological conditions of diverse etiologies that affect the testis or
the seminal pathway. No genetic component is present. The second variety is
characterized by a specific phenotype that affects most spermatozoa in all patients
suffering from the same condition. These alterations may be called systematic
anomalies because the sperm phenotype involves specific organelles and repeats in
most spermatozoa. Systematic alterations show family clustering and have proven
or suspected genetic origin. To this variety belong acephalic spermatozoa (Perotti
et al.
1981
; Chemes et al.
1987b
,
1999
), round head acrosomeless spermatozoa
(Holstein et al.
1973
; Nistal et al.
1978
), the miniacrosome sperm defect
(Baccetti et al.
1991
), Dysplasia of the Fibrous Sheath (DFS or stump tail defect,
Chemes et al.
1987a
,
1998
), and the dynein-deficient axonemes of Primary Ciliary
Diskinesia (PCD, Azfelius et al.
1975
). Each of these phenotypes is the conse-
quence of distinctive pathologic mechanisms involving different sperm organelles.
Headless sperm flagella, loose heads, and abnormal head-tail alignment are the
distinguishing features of a human syndrome of genetic origin characterized by
abnormalities in sperm centrioles and the head-neck junction. Later, we will
review what is currently known on this interesting sperm pathology.
Various kinds of defects in centrosomes and cilia have been reported in patients
suffering from ''ciliopathies'', a group of disorders of ciliated cells caused by
mutations in different genes (Tammachote et al.
2009
). These comprise syndromes
affecting CNS, eyes, kidneys, biliary ducts, respiratory tract, etc. Among them,
lack of dynein arms or other axonemal components is the structural basis of
immotility in respiratory cilia and sperm flagella in patients with PCD (Afzelius
et al.
1975
; reviewed by Chemes and Rawe
2003
).
As pointed out by Schatten and Sun (
2009
), even though genetic components
most likely play a role in centrosome pathologies, these can also have acquired
origins, including exposure to a variety of environmental factors or toxic com-
pounds that can disrupt centrosomal function.
Examining the ultrastructure of zygotes and aster development after fertiliza-
tions with abnormal spermatozoa, Sathananthan (
1994
) and Van Blerkom (
1996
)
