A French bulldog with sex reversal has been identified in Spain.
Tana was brought to a veterinary centre for her first vaccination. Specialists there were alerted by the size of her clitoris, which was ‘larger than normal’.
They carried out tests, which revealed the first ever genetic alteration ever detected in the reproductive system of this breed – the female puppy had cryptorchid testicles (outside the scrotum).
Genetic alteration of the reproductive system or sexual reversal has been described in many species, such as goats, pigs, horses and even human beings, said Marcos Campos, lead author and a researcher at the CEU-Cardenal Herrera University.
Tana, which was three months old when brought for her first consultation, presented symptoms compatible with having a genetic alteration of the reproductive system – she had a large clitoris.
“She was a chromosomally XX female but with masculine gonads (cryptorchid testicles) due to the presence of other genes that determined the formation of testicles in the absence of the genes present on the Y chromosome,” said Campos.
This alteration, which has also been described in another 18 breeds of dog around the world, is ‘uncommon but it can occur’.
Sex reversal causes sterility and, over the long term, may predispose the animal to pathologies such as infections or tumours of the gonads, ‘since this is not a normal genital’, said Campos.
The study showed that the urethra ended in the bladder, and the clitoris, which was 0.8 cm long, contained a penis bone, which predisposed it to urinary infections that would likely cause the dog to be infertile.
The puppy, the first documented case anywhere in the world of a French bulldog with this alteration, had a low level of masculinisation, since the vulva was normal despite the size of the clitoris.
The study has been published in Reproduction in Domestic Animals.