Pregnancy in an SRY-Negative XX Developmental Sex Disorder Pig After Removing an Ovotestis

A 2-year-old Large White research gilt was presented to the Comparative Theriogenology service at WSU for infertility. She was produced from the transfer of genetically modified embryos obtained via in vitro fertilization (IVF) that had been treated with CRISPR-Cas9 reagents to mutate the NANOS2 gene. Since birth, the gilt showed a so-called "skyhook" vulva and abnormal estrous cycles. She was artificially inseminated multiple times, starting at 5 months of age, with semen from a proven fertile boar, but never conceived. On transabdominal ultrasonography of the reproductive tract, a unilateral ovotestis was suspected. An exploratory laparotomy was performed and confirmed the presence of ovarian and testicular tissue on her right gonad. The diagnosis was confirmed by histology following unilateral gonadectomy. The cytogenic evaluation revealed the gilt to be XX 38, SRY-negative. The gilt showed estrus signs 4 months after surgery, and artificial insemination was performed, which resulted in pregnancy. She delivered six piglets. Necropsy was performed following humane euthanasia. Several abnormalities of the reproductive tract were discovered, including a unilateral mucometra due to a complete septum, preventing communication between the right uterine horn and the body of the uterus. This case is novel because it demonstrates that surgical removal is an effective treatment for fertility in SRY-negative XX DSD gilts with partial masculinization, posing the presence of a normal ovary and a developed oviduct and uterine horn.