Hermaphroditism

From Dog
Enlarged clitoris seen at physical examination in a hermaphrodite dog with a normal uterus and gonads resembling testes. [1]

Hermaphroditism (Intersex) is a congenital disorder in sexual development, characterized by the presence of male and female sex organs[2].

Intersex can be divided into two main types: true hermaphrodites and psuedohermaphrodites.

In true hermaphrodite, phenotypes can be XX males (normally XY) with testes and normal external genitalia, XX males with testes and ambiguous genitalia, and XX true hermaphrodites with ovotestes and ambiguous genitalia. XX males are reported in upwards of 20 breeds[3]. An enlarged clitoris is a consistent clinical observation, 90% of which contain ossified tissue consistent with an os penis. XX disorders of sexual development in the dog can be sporadic but will often display familial clustering; pedigrees are usually consistent with patterns of autosomal recessive heredity but are sometimes described as autosomal dominant[4].

Female hermaphrodite dogs normally display clitoromegaly but otherwise may appear normal except for some increase in abdominal size[5].

Pseudohermaphrodites often display a combination of genitals such a fleshy mass protruding from the vulva. Upon operation the ovaries appear to have testicular growth associated with them and are known as ovotestes[6]. Pseudohermaphroditism is also associated with Sertoli cell tumor and cryptorchidism[7][8].

Intersex dogs are usually infertile and are susceptible to prostatic adenocarcinoma and prostatitis.

Clinical signs are often difficult to determine as most are diagnosed during routine desexing procedures.

A differential diagnosis would include persistent Müllerian duct syndrome and feminizing syndrome associated with Sertoli cell tumor and prostatic hyperplasia.

Treatment in most cases is elective neutering.

References

  1. Silversides DW et al (2011) Disorder of sex development (XX male, SRY negative) in a French bulldog. Can Vet J 52(6):670-672
  2. Buijtels JJ et al(2012) Disorders of sexual development and associated changes in the pituitary-gonadal axis in dogs. Theriogenology 78(7):1618-1626
  3. Meyers-Wallen VN et al (1999) Sry-negative XX sex reversal in purebred dogs. Mol Reprod Dev 53:266–273
  4. Pujar S et al (2005) Exclusion of Lhx9 as a candidate gene for Sry-negative XX sex reversal in the American cocker spaniel model. J Hered 96:452–454
  5. Groppetti D et al (2012) XX SRY-negative true hermaphrodism in two dogs: clinical, morphological, genetic and cytogenetic studies. Sex Dev 6(1-3):135-142
  6. LIDA
  7. Svendsen CK et al (1985) Two cases of male pseudohermaphroditism in the dog. Clinical, macroscopic, karyotypic and therapeutic features. Nord Vet Med 37(6):358-363
  8. Kelch RP et al (1972) Estradiol and testosterone secretion by human, simian, and canine testes, in males with hypogonadism and in male pseudohermaphrodites with the feminizing testes syndrome. J Clin Invest 51(4):824-830