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

## TL;DR

A pig with a rare genetic condition successfully gave birth after surgery removed an abnormal gonad.

## Contribution

This is the first reported case of successful pregnancy in an SRY-negative XX DSD pig after surgical removal of an ovotestis.

## Key findings

- Surgical removal of a unilateral ovotestis enabled a genetically modified SRY-negative XX gilt to become pregnant and deliver six piglets.
- The gilt exhibited reproductive tract abnormalities, including a complete septum causing unilateral mucometra.
- The case demonstrates that surgical intervention can restore fertility in SRY-negative XX DSD pigs with partial masculinization.

## Abstract

Disorders of sex development (DSDs) in mammals are relatively common in veterinary medicine. They often present as complaints related to infertility and abnormal behavior in animals. Many incidences of DSDs occur when there is a mismatch between chromosomal gender (XY/XX) and gonadal development (testes/ovaries), and produce a range of phenotypic abnormalities. These conditions have historically been referred to as “hermaphroditism”. Reports of SRY-negative DSDs in domestic animals are infrequent. This case is notable as it is the first to describe surgical correction involving the removal of a unilateral ovotestis in a pig, who was then able to carry a normal pregnancy to term.

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.