We welcome Dr. Roger Carnes M.D., a retired obstetrician-gynecologist from Washington State as guest editor/writer for HDDW. Here he reviews the process of genetic testing on embryos for couples at risk for Huntington's, and reports on information obtained from an interview with Dr. Mark Hughes, whose laboratory performs all the testing performed in the U.S.

A couple with one partner gene positive or at risk for Huntington's Disease with unknown gene status may choose in vitro fertilization (IVF) with preimplantation genetic diagnosis (PGD) to try to insure that their newborn child is free of Huntington's Disease. According to information obtained from Dr. Mark Hughs of Michigan whose laboratory performs all of the gene testing for this procedure, 176 couples at risk of transmitting Huntington's Disease had this procedure performed in 2006.

The Procedure During an IVF cycle, medications that stimulate ovulation are given so that multiple eggs develop. Ovarian egg development is then monitored with blood estradiol and sound wave procedures. Human chorionic gonadotropin (HCG), which is a pregnancy hormone, is injected as the eggs mature. The eggs are then retrieved with a needle under ultra sound guidance from the ovary via the vagina.

Next, the eggs are incubated with the male partner's sperm overnight. The maturing embryos are examined on day three and a small number of cells around each embryo are sent to Dr. Hughes' lab for genetic evaluation. Just two days later the genetics lab reveals which of the embryos are not Huntington's Disease carriers. The non-HD embryos are returned to the mother's uterus through her cervix that same day.

Her pregnancy is then carefully monitored until delivery. A more detailed review of IVF can be found at Seattle Reproductive Medicine.

The table to the right gives success rates for pregnancy in couples using IVF who have infertility. There is unfortunately no data to assess success rates for couples using PGD gene testing prior to IVF. However it is likely that success rates would be higher for couples at risk for Huntington's who do not have known infertility.
Mother's Age Live Birth Rate per IVF Cycle
< 35 52.5%
35-37 48.6%
38-40 38.5%
41-42 23.7%
> 42 16.7%

Costs Medical insurance does not cover the costs of these treatments. Each IVF cycle costs in the range of $20,000. For those with infertility problems, two, three, or more cycles may be required. In this situation, total cost, excluding obstetric care, can easily run $40,000 to $100,000. These numbers are for infertile couples undergoing IVF. Remember that many couples at risk for having a baby with HD are not infertile and their success rates are likely to be higher and average costs lower.

IVF becomes less successful as women age. Another option for the older gene positive woman is donor egg IVF from a younger woman. If the man is gene positive, the more economical donor sperm insemination is possible.

Links to related material
Information on in vitro fertilization (IVF) from Seattle Reproductive Medicine and WebMD

Information on preimplantation genetic diagnosis (PGD) from Genesis Genetics Institute