As 15-month-old Addyson Valley got progressively worse in intensive care, her doctors decided to take her off formula, the Milwaukee Journal-Sentinel reports. One of them, Children's Hospital of Wisconsin's Alan Mayer, says he thought to himself, "It's the Nic story again."
In 2009, Mayer and his colleagues at Children's and Medical College of Wisconsin sequenced the exome of Nic Volker, a young boy who was suffering from an undiagnosed disease in which food caused holes to develop in his intestines, the Journal-Sentinel says. By examining his exome, Mayer and his team found an XIAP gene mutation, which they treated using umbilical cord blood.
And so Mayer, now at GI Associates, took the same approach with Addyson. Sequencing her DNA revealed she had two different mutations in the DGAT1 gene, which prevented her from making an enzyme that's needed to absorb fat. She's now on a fat-free diet and receives supplemental fat, which is needed for growth, through an IV. The Journal-Sentinel notes that while she's still smaller than other infants her age, she's doing well.
Mayer adds that he reached out to other gastroenterologists to see if they've had other patients with DGAT1 deficiency, and he learned that there is a handful of patients with the condition, all of whom were diagnosed through sequencing.
"This disease didn't exist until exome sequencing," Mayer tells the Journal-Sentinel.