First reported case: preimplantation dx rules out retinoblastoma.(Gynecology)

For the first time, preimplantation genetic diagnosis for retinoblastoma has ensured the birth of a healthy infant who does not carry the genetic germline for the devastating disease, reported Dr. Kangpu Xu and his colleagues at Cornell University, New York.

"Preimplantation genetic diagnosis for retinoblastoma offers families the opportunity to potentially avoid the loss of life, eyes, and vision in subsequent generations to this genetic cancer syndrome," the investigators said. "These considerations, as well as the avoidance of a decision to terminate an ongoing pregnancy, are seen as the benefits of this technology over other prenatal (postimplantation) diagnostic options" (Am. J. Ophthalmol, 137[1]: 18-23, 2004).

The singleton pregnancy resulted from an in vitro fertilization (IVF) cycle that yielded 12 embryos: 7 embryos were found to be unaffected and 5 were implanted.

The 33-year-old father is affected with retinoblastoma. Individuals with the disease have a 50% chance of passing the germline retinoblastoma gene (RB1) mutation to their offspring. The couple already has one daughter affected with the cancer. Although her retinoblastomas were successfully treated in infancy, at age 2 years she was diagnosed with a pineal tumor, a common occurrence since these children face a sharp increase in the risk of developing multiple cancers.

About 1% of patients with bilateral retinoblastoma develop a second primary neoplasm each year; at least 50% of these patients die from their tumors, they said.

The couple underwent two IVF cycles. In the first cycle, 12 oocytes were fertilized and underwent a single-cell genetic analysis by nested polymerase chain reaction. Four embryos were identified as unaffected, and three were transferred. A clinical pregnancy did not occur.

In the ...