Inheritance of Cryptorchidism

Amelia Roberts

What is crytporchidism?

One or both testes are not descended into the scrotum.

This is a sex-linked, polygenic congenital trait.

Unilateral (one-sided) cryptorchids will be infertile on the affected side, but bilateral cryptorchids will be entirely infertile.

The best management practice is to cull or not breed cryptorchid individuals.

Species Affected

Virtually all species are at risk: cases have been reported in...
  • Horses
  • Humans
  • Cows
  • Pigs
  • Sheep
  • Dogs
  • Cats
Just to name a few.

Method of Transmission

The sire or father carries the trait and passes it to his son(s) because the trait is carried on the Y chromosome. This fact is why it is called sex-linked, and autosomal. The trait is also polygenic in that it is affected by multiple genes; just because an individual has the genes for it (genotype), they may not express the trait (phenotype).

Prognosis: no effect on quality and quantity of life, although it is not beneficial to retain a cryptorchid in the breeding pool because of the decrease in fertility.

Management: the only management technique available is to not breed these individuals, or to cull them.

Question

How ethical is it to cull unilateral cryptorchid individuals, when they may still be fertile?

Sources

Ferlin, A., M.S. Rocca, C. Vinanzi, M. Ghezzi, A. Di Nisio, and C. Foresta. 2015. Fertility and sterility. Elsevier for the American Society for Reproductive Medicine. DOI: 10.1016/j.fertnstert.2015.04.017.

Hutson, J.M, A. Balic, T. 2010. Nation, and B. Southwell. Cryptorchidism. Seminars in Pediatric Surgery v:19:3(215-224). Department of Paediatrics, University of Melbourne, Douglas Stephens Surgical Research Laboratory and Murdoch Childrens Research Institute, Department of Urology, Royal Children's Hospital, Melbourne, Victoria, Australia. Doi:10.1053/j.sempedsurg.2010.04.001.

Nef, S. and L.F. Parada. 1999. Cryptorchidism in mice mutant for Insl-3. Nature Genetics, 22(pp.295-299). Center for Developmental Biology, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas, Texas 75235-9133, USA. Doi:
10.1038/10364

Shoukry, M., K. Pojak, and M.S. Choudhry. 2015. Cryptorchidism and the value of ultrasonography. Royal College of Surgeons of England, vol:97(1). pp.56-58. DOI: 10.1308/003588414X14055925058715