I just want to get this out there for everyone in the GSP world to see. Hermaphroditism is a concern in our breed, and everyone needs to know about it.
This is a 1 in 10,000 disorder that is being treated as a recessive gene trait. Meaning that both the sire and dam have to be carriers in order for one of the offspring to be affected. Both parents will not show signs of the disorder and can still be carriers. And I know 1 in 10,000 seem like rather unlikely odds but I have seen two hermaphrodites in the past three months, it isn't as rare as one may think!
The following information is from the wonderful Dr. Vicki Meyers-Wallen's Page from Cornell University http://bakerinstitute.vet.cornell.edu/faculty/page.php?id=206
SRY-negative XX sex reversal is an inherited disorder that causes infertility and sterility in some breeds of purebred dogs. At present, this inherited disorder is well documented in the following breeds in the USA:
American and English cocker spaniels
Beagle
Chinese pug
German shorthaired pointer
Kerry blue terrier
Norwegian elkhound
Soft-coated wheaten terrier
Weimaraner
Affected dogs have female chromosomes (XX), although dogs with male sex chromosomes (XY) can be carriers of XXSR. Normal dogs with female sex chromosomes develop only ovaries. Dogs affected with XXSR usually develop both ovarian and testis tissue (ovotestes). On rare occasions, affected dogs develop only testis tissue. As a result, the rest of the reproductive tract develops abnormally. This leads to infertility and sterility.
Externally - Affected dogs can have any of the following signs:
A vulva that is shaped like a prepuce.
A. Normal vulva in a female pup. B. Prepuce-like genitals in an XXSR affected littermate to (A).
An enlarged clitoris (containing a bone) that may protrude from the vulva.
Dog affected with XXSR showing enlarged clitoris containing a bone (arrow). This structure often protrudes from the vulva in affected dogs.
A longer distance between the anus and the vulva than is normally seen in females (the vulva may be located very near the belly) or a small prepuce.
A. Normal pup on the left showing position of umbilicus (arrowhead) and prepuce (arrow). The littermate on the right is affected with XXSR. Note the difference in position of the small prepuce (arrow) in relationship to the umbilicus (arrowhead) as compared to the normal male on the left. B. Affected pup from (A) at approximately 10 months of age. Note abnormal conformation of the prepuce/vulva (arrow).
If they have a penis-like structure they have hypospadias (the urethra does not open at the tip but opens farther caudally).
Close up of a penis-like structure of a dog affected with XXSR showing hypospadias. A catheter has been placed in the urethra. The urethral orifice (arrow) is located farther caudally than the normal position (indicated by arrowhead).
Internally - Affected dogs usually have:
- Bilateral ovotestes or testes
- One ovotestis and one ovary
Microscopic views of gonads from dogs affected with XXSR A. Ovotestis. Arrow indicates testis tissue in the center of the ovotestis. Arrowhead indicates ovarian tissue with follicles developing on the external surface of the ovotestis. B. Ovotestis at higher power magnification showing ovarian tissue at the surface (arrowhead) and testis tissue internally (arrow). C. Higher power magnification of the testis portion of the ovotestis. Seminiferous tubules contain only Sertoli cells (arrow) and contain no sperm producing cells.
Most often, affected dogs cannot be differentiated from normal females during a spay/neuter operation even if the veterinarian is an expert in XXSR because testicular tissue is often in the center of the gonad. Carriers look like normal females or normal males. Correct diagnosis depends upon microscopic examination of the gonads by a pathologist who is familiar with XXSR. When this is done, either one ovary and an ovotestis, two ovotestes, or two testes are usually found.
Uterus and gonads of a dog affected with XXSR. Double arrows indicate the uterine horns. Single arrow indicates an epididymis adjacent to an ovotestis.
When only testes are found, they are usually in the abdomen. All affected dogs have a complete uterus. Many have an epididymis adjacent to the ovotestis or testis.
Also, all affected dogs have female sex chromosomes (XX), as determined by chromosome analysis (karyotype) and no Y chromosome.
At present, correct diagnosis of affected dogs is difficult, and there is no practical method to identify carriers.
PCR Tests Polymerase Chain Reaction (PCR) tests for the presence of canine Sry in DNA from normal and affected dogs. The Sry gene is normally located only on the Y chromosome. Normal female (F) and affected (A) dogs do not have Sry in their DNA. Normal males (M) have Sry. Both normal and affected dogs have the control product from the HPRT gene, which is on the X chromosome.
We hope to increase breeders' awareness of XXSR by describing the common findings in affected dogs. We need to know if this problem has been recognized in your breeds and how many dogs have been affected.
We are working to identify the gene that causes this problem so that we can develop a DNA test. A DNA test will allow us to clearly identify both carrier and affected dogs, providing a practical method to improve breeding performance in these breeds.
You can help by contacting Dr. Vicki Meyers-Wallen if you think you have an affected dog. All information will be kept in the strictest confidence. If you wish, we can assist you and your veterinarian in diagnosis and genetic counseling. |