As she plummeted toward the Wisconsin countryside below, JorJan Borlin tried desperately to straighten out her parachute. The lines had tangled, creating what is known as a “Mae West” effect, the chute ballooning out between them. It was only her second jump and the ground was coming up on her much too fast for her to pull out her reserve chute.

Teddy was an exceptional child in many ways. For one thing, he weighed nine pounds, 12 ounces when he was born, causing the attending nurse to remark, “This one must have come with his own paper route.” For another, he appeared to be surprisingly mature for his age. His mother noted that he had the wizened, knowing eyes of an old sage.

Sandhoff’s disease is rare. It is estimated that perhaps 1 in 100,000 people carry the defective gene. Symptoms are similar to Tay-Sachs disease, but Tay-Sachs is much more common among all population groups. There have been only 12 to 15 documented cases of Sandhoff’s disease in the U.S. since it was identified around 20 years ago.

Neither JorJan nor Peter had any idea that they were carriers. It’s possible that they were the only two people living in the city of Madison, Wisconsin, who harbored the deadly gene. The chances of two carriers falling within the same age group and being attracted to one another is infinitesimal.

“We thought maybe we weren’t doing enough to stimulate him,” says Peter. “We went out and bought him all kinds of toys to stimulate his big muscles. He never learned to crawl and could only sit up if you helped him.”

Best of Chicago voting is live now. Vote for your favorites »

“What we really hoped to hear was, ‘Oh, you guys are just being silly, he’s just fine,’” JorJan says.