Mercies in Disguise by Gina Kolata ****

Mercies in Disguise by Gina Kolata is two books. First, the science journey to understand Gerstmann–Sträussler–Scheinker (GSS) syndrome and related diseases. Two Nobel prizes were awarded along the way. Second is about a family's challenges with this hereditary disease, which strikes mid-life and is invariably fatal after a long downhill deterioration.


First the science story: GSS, Creutzfeldt-Jakob Disease (CJD), Mad Cow Disease, and Scrapie (sheep and goats) are a family of diseases that are both contagious and hereditary. In the case of contagious transmission, exposure to the contagion and disease symptoms are separated by years or decades. In the case of inheritance, symptoms do not appear for similarly long times.

Ultimately, the diseases are not caused by any living disease agent. Not bacteria. Not viruses. Nothing that contained DNA or RNA. This was a totally new disease mechanism. A protein which is now called a prion. The genetic mutation for GSS was discovered through two years of DNA sequencing. Today, it could be done in two days.

While people can now be tested for these diseases, there is no cure in sight.

Second, the people story. If someone is identified with GSS, they will suffer a debilitating, fatal disease in middle age, and have a 50% chance of passing this disease on to their children. While there is no cure, science offers some alternatives for couples who would like to have children.

The couple can become pregnant and screen for GSS, much the same as couples screen for Downs Syndrome. If the baby has GSS, the couple can choose to terminate the pregnancy or not. The other alternative is IVF. In this case, before the embryo is implanted, it can similarly be screened and only implant those embryos without the GSS mutation.

Much of the drama of the second part deals with conflicts among the options provided by science and the dictates of religions. As if to emphasize the impact of religious doctrines, the couple is mixed Christian and Jewish. The families seem to have the same problems with the mixed aspect of the union as the genetic screening and terminations.

The first part of the book will appeal readers interested in the workings of medical research. The second part of the book is all about difficulties when religion and science offer conflicting alternatives. The book is helpfully divided into two parts for readers who are only interested in one of these two stories.