Cryptorchidism (hidden testis) is one of the most common human birth defects. It affects three out of every 100 newborn males. During embryonic development, the testicle changes its position from adjacent to the fetal kidney to its final location in the scrotum. A cord-like structure called the gubernaculum aids this testicular movement. Although there are many theories concerning how the testis descends, aberration in one or more molecules may result in testicular maldescent. In some cases, hormone shots can induce descent. However, surgery is typically required to correct the undescended testicle. Therapy is mandatory to diminish the risk of infertility, to monitor for testis cancer, and for cosmetic reasons.

Recently, at UT Southwestern Medical Center, a hormone known as Insulin-3 (Insl3-also known as Relaxin-like factor or Leydig Insulin-like hormone) was knocked out (i.e., the DNA of the mice is engineered so the gene for Insulin-3 is absent) in mice. The single phenotypic aberration noted was intra-abdominal cryptorchidism due to abnormal gubernaculum formation (Nef, S. and Parada, L.F. Cryptorchidism in mice mutant for Insl3. Nature Genetics 22:295-299, 1999).

In this collaborative project, the two main goals are:

• Assess the outcomes of surgery in Insl3 mutant mice
• Participate in screening human patient samples for mutation and expression of the Insl3 gene
• This project applies molecular biological techniques using the knock-out mouse model and patient samples. It will contribute to the understanding of a common birth defect, thereby helping many affected children.

Understanding Hypospadias at the Molecular Level

Genetics of Calcium Oxalate Stone Disease

Research Interests

Principal Investigator:

Linda Baker, M.D.: 214-648-3865

Linda.Baker@utsouthwestern.edu

For more information about the Department of Urology, contact:

Phone: 214-648-4765, FAX: 214-648-4789

Mailing Address: 5323 Harry Hines Blvd., J8.148, Dallas, TX 75390-9110