Elizabeth Joshi of Evansville, Ill., could have been helped by this test, as she spent months trying to get a diagnosis for her son with Joubert syndrome, a rare genetic disorder that affects the brain's cerebellum.
Though it can vary in severity, it causes breathing problems, seizures and often fatal kidney disease. Only about 650 families in the U.S. are affected.
"Not knowing what was wrong with him hit me like a ton of bricks," said Joshi, 40, and a former lawyer.
Shaan, now 6, is unable to eat solid foods and cannot speak or walk. How long he will live is "a big question mark," according to his mother.
"He seems very aware of what's going on," said Joshi. "But it's so hard on him physically for him to express what he needs and wants and leads to a lot of aggravation for him. It's a daily struggle."
Shaan's 8-year-old sister in unaffected, but Joshi has decided not to have any more children.
"We are personally not willing to roll that dice," she said, "knowing what he deals with."