Four-month-old Ainsley Cardente smiles, enjoys "helicopter" rides from her mum and protests when lunch is late. Perfectly ordinary, all of it. And her life is expected to remain that way thanks to a $US2.1m ($AU3.1m) treatment recently doctors recently infused into her little body.
Ainsley was born with a rare genetic disorder called spinal muscular atrophy, or SMA, that kills most babies by age two. Rarely, there are less severe versions like the one that afflicts Ainsley, from Annapolis in the US, that lead to a slower but still catastrophic decline. However that decline has been halted by the medication known Zolgensma.
"She'll never be in a wheelchair; she'll never feel like a sick person," said Kate Cardente, Ainsley's mother, a physician assistant from the Annapolis suburb of Arnold. "She'll never remember it."
Zolgensma, approved in the US for children under age two, works by replacing the missing or nonworking gene permanently with one dose.
It is not yet approved for use in Australia but some local families, including that of Queensland toddler Wynter Clarkson, are desperately trying to access Zolgensma for their children.
Wynter appeared "perfectly healthy" when she was born, but that changed when she was diagnosed with SMA at just three months of age.
"Our world came crashing down," Wynter's parents Jamie and Kellee write on their GoFundMe page.
"Our little girl is unable to sit, crawl, walk, run or eat properly because of this disease, and it is heartbreaking for us to watch her struggles with what most of us take for granted."
Wynter's parents are in a race against time Zolgensma needs to be administered before a child's second birthday and their daughter is now 19-months-old.
"(Zolgensma) is the best on the market for SMA and we are desperately wanting to get it for our little girl," they write. "Naturally we as parents want the best treatment we can get for her."
Baby Ainsley almost didn't get Zolgensma treatment either - due to its prohibitive cost.
On the market in the US since May, it's the nation's most expensive prescription drug and the Cardentes' insurer initially refused to cover the cost. So Cardente and her husband, David, fought to get it approved. A letter from Ainsley's doctor at Johns Hopkins Hospital, a top SMA expert, helped win coverage.
"We have a lot to be thankful for this year," Ms Cardente said at a Johns Hopkins outpatient centre in Dundalk, as a line pumped the drug into Ainsley's foot over about an hour.
But the emotional and potential financial burden is likely familiar to many families without the ability to pay out of pocket for necessary drugs. As more gene therapies and other innovative - and ultra-expensive - treatments are approved in coming years, such challenges are likely to become more common even as they engender hope.
"Ainsley is going to be normal, and, oh my God, that is so great," said Dr Tom Crawford, the Hopkins pediatric neurologist who treats Ainsley and every baby with SMA in the region. "This is a new world, but society is going to have to figure out how to pay."
Spinal muscular atrophy is a neuromuscular disorder that leads to progressive muscle weakness, paralysis and most often death. It's caused by the absence of a gene that produces a critical protein needed to preserve motor neurons. Without it, those neurons rapidly die.
AveXis, the Illinois-based biotech company that developed Zolgensma, notes that its cost is lower than the lifetime cost of the other main treatment for the disease, which can exceed $4 million over a decade. Biogen's Spinraza was approved in 2016 by the US Food and Drug Administration but requires regular and costly spinal injections to stem deterioration.
Dr Crawford smiled as he watched a staff of nurses and others tend to Ainsley last month. They loaded a large syringe with the drug, which had been delivered by special courier from a manufacturing plant near Chicago in a small box, which was later presented to the Cardentes with a bow. Ainsley sat on her mother's lap unmoved by the momentousness of the day.
Over the last quarter century, Crawford says he attended dozens of those deaths from what was known as "the most hopeless disease in pediatrics."
On this day, however, he marvelled at no longer being "a hospice doctor." Beyond a small amount of treatable liver damage, he expects Ainsley to do normal things like go to school and prom and have a career and a family.
She was the second baby for whom Dr Crawford secured approval to treat with Zolgensma, and he is unsure of the battles ahead.
Ainsley is doing well now, even rolling over from back to front and sometimes front to back. The Cardentes said they'd like to figure out a way to help other families. Kate Cardente said that might mean just telling them how they advocated for Ainsley.
"There really isn't a blueprint for the next family," she said. "I'm just so glad we got our miracle day."
This is an edited version of the story which first appeared in The Baltimore Sun.