Chapter

XY Male Pseudohermaphroditism

01/2009; ISBN: ISBN 978-1-60741-304-2 In book: Sex Chromosomes: Genetics, Abnormalities, and Disorders, Chapter: Chapter 9, Publisher: Nova Science Publishers Inc, Editors: C. N. Weingarten, S.E. Jefferson, pp.165-190

ABSTRACT Sex chromosome anomalies are frequently expressed as malformations of the
reproductive organs and constitute sporadic birth defects in domestic animals, which
often leads to infertility. In the presence of a normal karyotype, abnormalities in the
genital tract development can occur. Intersex condition is relatively frequent in goats and
pigs, but less frequent in sheep and dogs. In ruminants, most intersexes conditions
correspond to XX/XY haematopoietic chimaeras and fit in the freemartinism syndrome.
However, sporadically cases of male pseudohermaphroditism are reported that can be
differentiated from the freemartinism syndrome through the karyotype as well as by the
morphological characteristics of the genital tract. These are XY animals that evidence a
variable differentiation of the genital tract, owing to varying degrees of the external
genitalia and paramesonephric ducts associated with inadequate production of
testosterone or Anti-Müllerian Hormone by the fetal testes. Male pseudohermaphroditism
may occur in distinct varieties. Male pseudohermaphroditism includes male to female sex
reversal a condition where, consecutive to a disrupted gonadal differentiation or to an
abnormal development of the Leydig cells, testosterone production is impaired; this
syndrome may present distinct clinical gradations, whether a streak gonad or a
dysgenesic gonad develops. Total absence of androgens induces feminization of the
reproductive tract, while impaired testosterone production and accumulation of
testosterone precursors may originate ambiguous genitalia. In the androgen insensitivity
syndrome, another form of male pseudohermaphroditism also called the testicular
feminization syndrome, despite the presence of testes and a XY karyotype, almost
normal-appearing female phenotypes can be found. This condition is associated to a
defect in the androgen receptor mechanism that leads to a resistance to the testosterone
action at the cellular level in the external genitalia embryonic rudiments. A steroid 5α-reductase deficiency, impairing dihydrotestosterone formation, might also be responsible
for male pseudohermaphroditism. Frequently, animals usually are XY individuals
evidencing female-like or ambiguous external genitalia. Persistency of the Müllerian
ducts is another male pseudohermaphroditism condition, associated with the inadequate
production of Anti-Müllerian Hormone or to the absence of its receptors, which can
reveal female or ambiguous external genitalia.
Based on three distinct forms of male pseudohermaphroditism recently evaluated by
our Clinical Services, the aims of this study includes the morphological, histological and
immunohistochemical description of this condition in normal XY karyotype males (in
both blood and fibroblast samples), and the discussion of the cases through a review of
the literature, in order to improve our knowledge of male pseudohermaphroditism.

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    ABSTRACT: CASE HISTORY: An 8-month-old Labrador Retriever was referred with a history of ambiguous external genitalia. CLINICAL FINDINGS AND TREATMENT: Clitoromegaly within apparent vulval folds, and an adjacent subcutaneous mass were noticed on external examination. An intra-abdominal testicle, with epididymis and suspected vas deferens ducts, was found during exploratory celiotomy. Incision over the subcutaneous mass revealed the accompanying testicle. Clitoridectomy was performed and an os clitoris removed. Normal juvenile testes were diagnosed on histology of the gonads. Chromosomal studies revealed a normal 78, XY male chromosomal constitution. Due to the combination of a male karyotype (78, XY), the presence of testicular tissue in the gonads, and the appearance of the external genitalia, a diagnosis of male pseudohermaphroditism (MPH) was made. CLINICAL RELEVANCE: This case presents the first report of MPH in a Labrador Retriever, and highlights the diagnostic steps recommended when confronted with a dog with ambiguous external genitalia.
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    ABSTRACT: With the purpose to characterize the ultrasonographic features of the dog penis, 20 healthy dogs aged from 2 to 11 years old were used. Ultrasonography was performed using a 5-9MHz linear probe and a Philips HD3 scanner. Ultrasonograms were obtained at the penile body (pre- and post-scrotal sections) and at both the bulbus glandis and the pars longa glandis, with the dog placed in dorsal recumbency. The typical anatomy of the dog penis is easily demonstrated in ultrasonographic images, as revealed in this study. On ultrasonograms taken at the body level, the two corpora cavernosa showed a homogeneous, hypoechoic structure; ventrally, the corpus spongiosum appears as a slightly hyperechoic structure surrounding the urethra. In glans ultrasonograms, the most typical feature is the os penis, observed as a strong hyperechoic structure, whose acoustic shadow impairs the screening of adjacent tissues. Lining on its concavity, the corpus spongiosum is observed as a slightly hyperechoic tissue around the urethra. An ovoid, regularly hypoechoic tissue corresponding to the erectile tissue of the pars longa, surrounds these structures. The bulbus glandis is visualized as a regular hypoechoic structure with small anechoic areas, corresponding to sinusoidal spaces. The albuginea is evidenced as a well-defined, hyperechoic external layer. The preputial cavity appears as a thin anechoic layer surrounding the albuginea. The results of this study demonstrate that ultrasonographic assessment of the dog penis is easily performed and accurate enough for penile examination. Furthermore, ultrasonography of the dog penis can become an interesting diagnostic tool to explore in the canine practice, during breeding soundness evaluation and also whenever penile exposition is impossible to achieve.
    Animal Reproduction Science 07/2008; 106(1-2):174-80. · 1.90 Impact Factor
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    ABSTRACT: A review of the genetics of male undermasculinization must encompass a description of the embryology of the genital system. The dimorphism of sex development consequent upon the formation of a testis and the subsequent secretion of hormones to impose a male phenotype is highlighted. Thus, an understanding of the causes of male undermasculinization (manifest as XY sex reversal, complete and partial) includes reviewing the genetic factors which control testis determination and the production and action of testicular hormones. The study of disorders of male sex development has contributed substantially to knowledge of normal male development before birth. This knowledge has been complimented in recent years by the use of targeted murine gene disruption experiments to study the sex phenotype, although murine and human phenotypes are not always concordant. The investigation of disorders associated with male undermasculinization of prenatal onset is described briefly to complete the review.
    Clinical Endocrinology 02/2002; 56(1):1-18. · 3.40 Impact Factor

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