Major league baseball star and his wife turn to IVF to conceive child free of Huntington’s Disease

Joe Smith, pitcher for the Houston Astros, and his wife, sports reporter Allie LaForce. Smith’s family carries the gene for Huntington’s Disease. Photo courtesy of Huntington’s Disease Society for America website.

For many couples, one of the most monumental moments in life is the decision made to conceive a child together and start a family. The usual questions that come to mind typically relate to simple matters such as potential baby names, diapers, clothes, pacifiers, cribs, blankets, and stuffed animals. New parents will also think about what customs, languages, and set of principles they want to pass along to their child. But what if there was something they didn’t want to pass along to their child? What if there was a 50/50 chance of unintentionally passing along a debilitating genetic condition? For Houston Astros pitcher Joe Smith and his wife, sports reporter Allie LaForce, this situation was a devastating reality.

Joe’s grandmother and mother were both diagnosed with Huntington’s Disease (HD), so he has seen first hand the debilitating effects of this condition. HD is a genetically inherited, neurological condition that causes the progressive breakdown of nerve cells in the brain and has no known cure. It gradually deteriorates a person’s mental and physical abilities, making it difficult to recall things, walk, or even speak. According to statistics from Huntington’s Disease Society for America (HDSA), every child of a parent with HD has a 50/50 chance of inheriting the disease. Furthermore, there are approximately 30,000 Americans living with HD and 200,000 at-risk of inheriting the condition. It is because of these high risks that Joe and Allie have decided to conceive a child with the aid of in-vitro fertilization (IVF).

Through IVF, an ovum and sperm are combined outside the body to create a fertilized egg. This egg can be implanted into a woman’s uterus, allowing it to grow and develop. However, there is additional technology known as preimplantation genetic diagnosis (PGD) that can be used alongside IVF. With PGD-IVF, the fertilized eggs can be genetically tested before implantation. In Joe and Allie’s instance, PGD-IVF can be used to screen for HD, ensuring that the fertilized egg does not carry the disease prior to implantation.

In an interview with Morgan Radford on The Today Show, Joe and Allie discuss in detail how HD has impacted their loved ones and their decision to use PGD-IVF. The interview is available here.

In the interview, Joe Smith is quoted as saying, “I’m just taking out a 50/50 chance…I just want that [HD] gone.”

The California Institute for Regenerative Medicine (CIRM) has recently approved a $6 million grant geared towards HD. This funding is for late stage testing needed to apply to the US Food and Drug Administration for permission to start a clinical trial in people. You can read more details about this award from a previous blog post here.

Eggciting News: Scientists developed fertilized eggs from mouse stem cells

A really eggciting science story came out early this week that’s received a lot of attention. Scientists in Japan reported in the journal Nature that they’ve generated egg cells from mouse stem cells, and these eggs could be fertilized and developed into living, breathing mice.

This is the first time that scientists have reported the successful development of egg cells in the lab outside of an animal. Many implications emerge from this research like gaining a better understanding of human development, generating egg cells from other types of mammals and even helping infertile women become pregnant.

Making eggs from pluripotent stem cells

The egg cells, also known as oocytes, were generated from mouse embryonic stem cells and induced pluripotent stem cells derived from mouse skin cells in a culture dish. Both stem cell types are pluripotent, meaning that they can generate almost any cell type in the human body.

After generating the egg cells, the scientists fertilized the eggs through in vitro fertilization (IVF) using sperm from a healthy male mouse. They allowed the fertilized eggs to grow into two cell embryos which they then transplanted into female mice. 11 out of 316 embryos (or 3.5%) produced offspring, which were then able to reproduce after they matured into adults.

mice

These mice were born from artificial eggs that were made from stem cells in a dish. (K. Hayashi, Kyushu University)

Not perfect science

While impressive, this study did identify major issues with its egg-making technique. First, less than 5% of the embryos made from the stem-cell derived eggs developed into viable mice. Second, the scientists discovered that some of their lab-grown eggs (~18%) had abnormal numbers of chromosomes – an event that can prevent an embryo from developing or can cause genetic disorders in offspring.

Lastly, to generate mature egg cells, the scientists had to add cells taken from mouse embryos in pregnant mice to the culture dish. These outside cells acted as a support environment that helped the egg cells mature and were essential for their development. The scientists are working around this issue by developing artificial reagents that could hopefully replace the need for these cells.

Egg cells made from embryonic stem cells in a dish. (K. Hayashi, Kyushu University)

Egg cells made from embryonic stem cells in a dish. (K. Hayashi, Kyushu University)

Will human eggs be next?

A big discovery such as this one immediately raises ethical questions and concerns about whether scientists will attempt to generate artificial human egg cells in a dish. Such technology would be extremely valuable to women who do not have eggs or have problems getting pregnant. However, in the wrong hands, a lot could go wrong with this technology including the creation of genetically abnormal embryos.

In a Nature news release, Azim Surani who is well known in this area of research, said that these ethical issues should be discussed now and include the general public. “This is the right time to involve the wider public in these discussions, long before and in case the procedure becomes feasible in humans.”

In an interview with Phys.org , James Adjaye, another expert from Heinrich Heine University in Germany, raised the point that even if we did generate artificial human eggs, “the final and ultimate test for fully functional human ‘eggs in a dish’ would be the fertilization using IVF, which is also ethically not allowed.”

Looking forward, senior author on the Nature study, Katsuhiko Hayashi, predicted that in a decade, lab-grown “oocyte-like” human eggs will be available but probably not at a scale for fertility treatments. Because of the technical issues his study revealed, he commented, “It is too preliminary to use artificial oocytes in the clinic.”