By Elie Dolgin

In 1995, Randi Chapnik Myers chose to abort her pregnancy after a 20-week ultrasound revealed an extreme buildup of fluid inside the fetus’ skull. At the time, she and her husband Rob “were told it was not genetic,” recalls Chapnik Myers, a freelance journalist in Toronto. Besides, both partners had been tested as carriers for an ailment that affects the brain called Tay-Sachs disease, one of the most common life-threatening genetic disorders found to disproportionately affect Ashkenazi Jews like the Myerses. And “it didn’t ever actually occur to me that there could be another genetic recessive disease that we could share,” she says.

After giving birth to two healthy children in the late 1990s, the couple assumed they were in the clear. But when Chapnik Myers became pregnant again with twin girls in 2000 and the sonogram again showed the same brain swelling in one of the fetuses, the couple realized that genetics were likely to blame. Ultimately, doctors deduced that the Myerses each carried the same recessive mutation in a gene responsible for a rare genetic condition called Walker-Warburg syndrome, a severe form of congenital muscular dystrophy that causes most children to die before the age of three.

“From the day they’re born, it’s basically a miserable disease,” says Wendy Chung, a pediatrician and clinical geneticist at Columbia University Medical Center in New York who has treated children with the disease.

Since the Myerses’ harrowing experience, researchers have mapped the gene responsible for Walker-Warburg and developed a lab test to screen for the disease mutation. Recently, independent teams led by Chung and Christopher Walsh, a geneticist at Children’s Hospital Boston, have also shown in separate Israeli and American cohorts that around one in 150 people of Ashkenazi descent carry the disease-causing version of the gene—about twice the rate seen in the general population (Hum. Mutat. 29, E231–E241, 2008; Prenat. Diagn. 29, 560–569, 2009).

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