Phenotypic characterization of a pig with XX karyotype and ambiguous genitalia: Cytogenetic, endocrine, and histopathological evidence.
Abstract
XX male syndrome is a rare genetic disorder in humans, characterized by the presence of male or ambiguous genitalia in individuals with a female karyotype (2n = 44 + XX). This syndrome is most commonly attributed to the translocation of the SRY gene from the Y chromosome to the X chromosome; however, in some individuals, the SRY gene is not detected, suggesting alternative mechanisms such as chimerism or mosaicism. In pigs (Sus scrofa domestica), sexual differentiation also depends on the functional presence of the SRY gene. This study describes the case of a six-month-old pig with a 2n = 36 + XX karyotype and ambiguous genitalia, found on a farm in Piñas, Ecuador. Cytogenetic, endocrine, anatomical (macroscopic and histopathological), and necropsy studies were conducted to characterize the syndrome observed. Cytogenetic analyses revealed a normal female karyotype without evidence of numerical or structural chromosomal abnormalities, while hormonal evaluations showed atypical levels of testosterone and estradiol. Necropsy and histological examination identified abnormalities in the reproductive organs and urinary system. This case highlights the importance of recognizing and characterizing disorders of sexual development in pigs, both for clinical diagnosis and for a deeper understanding of the underlying genetic mechanisms.
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References
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