The way Michal Farley figures it, Addie Moser is one in 36 million.
Addie, 11, has Gorham's disease, a rare bone condition that has about 200 documented cases.
That's the best figure available, according to the Lymphangiomatosis and Gorham's Disease Alliance, and it's a statistic that includes both of those diseases, said Farley, Addie's legal guardian.
It's often misdiagnosed, too, so it's not known how many people are actually affected.
Gorham's is also known as "disappearing bone disease," or "vanishing bone disease."
In Addie's case, both her clavicle and scapula are gone.
"We were comparing X-rays in Denver, from last year to this year, and I'm not a doctor but you can see the bones are just gone," said Ryan Farley, Michal's husband.
"You try to explain to people, and I've done it many times," he said.
It always goes back to the same question: "How can bones just disappear inside your body?"
Bones naturally break down and regenerate constantly to maintain their mass, according to the LGDA website. In the case of Gorham's patients, that ratio is thrown off.
Addie's clavicle and scapula, for instance, began breaking down at a rapid rate and never grew back.
Addie, a chipper, active girl, likes soccer and piano. Soccer's out for now: A light fall in April fractured her brittle clavicle.
Bicycling, too, is on hold. She can still play the keyboard, though, continuing lessons that she started in September.
"I've played a lot of 'The Sound of Music' and I'm working on 'Fix You' by Coldplay, and we have lesson books. They're just little songs that we play," she said.
The muscles have compensated, which she's eager to point out. She did physical therapy every week for the past year, and can lift her arm high enough to play piano or go swimming.
"The physical stuff is something we're just going to keep an eye on," Ryan said.
In August 2013, Addie fell in the bathtub and fractured her scapula. It didn't heal, one of the manifesting signs of the disease.
She had several surgeries and was hospitalized for an infection in March 2014.
Their bone doctor, Joshua Klatt, and their pediatrician, Kathy Rogers, diagnosed it as Gorham's disease and recommended they go to the Colorado Children's Hospital in Aurora.
She spent a week there, and the Farleys were told they should monitor her every month with X-rays. They also performed a CT scan that summer, and kept sending images to Colorado.
In April 2014, she was hit from behind while playing soccer, fell and broke her clavicle. A follow-up visit and X-ray showed it wasn't healing.
In May, she showed Michal a large lump she'd developed under her arm.
They went to the doctor and had images sent to Denver. Then it began rapidly growing – Addie called it "a watermelon."
They made another trip to Denver, and doctors found that the left clavicle and remaining part of her left scapula were gone.
Even more frightening, they learned the disease had moved into her rib cage and neck, which could lead to amputations or infections if it doesn't stop spreading.
The radiation treatments began June 12, and continued Monday through Friday for five weeks. Her last treatment was July 17.
They targeted the rib cage and neck, which required a special molded mask to keep her head turned in the correct position.
Ryan said her resilience and positive attitude were remarkable amid all the heavy conversations with doctors, surgeons and oncologists.
"I can go get my mask," she said, and ran into the house – returning to show it off for some guests and laughing at the Farley kids' "alien activity" jokes.
Now they're waiting to do another MRI, within a month to three months, to see whether the radiation was effective.
That will determine the next course of treatment, and they're consulting with doctors to see what the options are. Because the disease is so rare, there are different opinions on how best to treat it.
The disease is also known to go into remission, or to spontaneously recur.
"It could affect her for the rest of her life," Michael said. "There are certain cases where it goes away, goes into remission forever."
It remains a "great unknown," she said.
Addie's mother died of brain cancer when the girl was 3 years old. The long treatment and death took a toll on her father.
The Farleys are close family friends, and last year assumed legal guardianship of Addie and her sisters Aidan, 18, and Anna, 12; and brother Anton, 17.
"They were going to be separated, and as a mother I refused to let that happen," Michal said.
Aidan is headed to Montana State University next year, and it's the last year that the children could be together as a family.
So the Farleys added the Moser children to their young household: Shamus, 10; Eli, 8; and Della, 5.
"There's been a lot of support from people who knew their mom, or know their dad and want to help us care for everybody," Michal said.
Volunteers, for instance, helped renovate the Farleys' garage so the teenagers could have their own space.
They also received financial help for the trips to Denver. The treatments have been covered by Medicaid, but Ryan wasn't able to work while he was in Colorado.
They set up a website, helpaddiemoser.com, where all the people involved in the Mosers' lives can get updates or make donations. The money goes into a medical fund for Addie, and to pay for future trips to Denver.
"It's been expensive, but with the support we've gotten we haven't had to use any of our own funds yet," Michal said.
The blended family has all been helping during the trying times.
"Every kid has had such a great attitude," Ryan said. "I think everyone has elevated that part of our family, without even asking or telling them to do something. ... I think we grew a lot as a big family this summer."
For now, they're monitoring her for any more manifestations of the disease and waiting for the next MRI.
Till then, they're providing a happy, normal life for the kids – they took them all to the Red Ants Pants Music Festival, all piled into an RV with nine seat belts.
"The attitude has been, we're going to do it and she's going to be OK. And we're just going to keep doing it and she's going to be OK," Michal said. "You can't worry about what you can't change, so we're going to keep living life, we're going to keep doing what we do, and keep having fun. And we'll take what we have to when it comes."