ATLANTA (FOX 5 Atlanta) - In many ways, Katherine Heath is a typical 15-month old. She loves bubbles, and snacks on Cheerios.
"She is hilarious," her mother May Heath says. "She laughs all the time. She is as rough as any little boy you've ever met."
But unlike other toddlers, Katherine has a team of pros at Children's Healthcare of Atlanta helping her learn how to walk, on a tiny artificial leg built just for her. Colleen Coulter, a physical therapist with Children's Limb Deficiency program, is on her knees, guiding Katherine's feed.
"Good girl, that was a great step," Coulter says, speaking to Katherine’s mother. "She's doing that herself. She's kicking."
Katherine was born with proximal femoral focal deficiency, or PFFD, a rare birth defect that impacts about 1 in 200,000 children.
She is missing part of her right femur, hip joint and pelvis.
And Mary and Joey Health, who were first-time parents, had no idea what this would mean for Katherine.
"It changes your world," Mary Heath says. "Everything you thought your child's life would be like will be different."
But, when Katherine was 7 days old, the Heaths took her to Children's top orthopedic surgeon, Dr. Robert Bruce, who said something Mary says stood out to her. It's guided her thinking ever since.
"He told us, 'Mary and Joe,' he said, 'Your daughter hasn't lost anything. He said, she was born perfectly. She will learn how to walk and how to do life just like every baby does.' He said, 'The only person who has lost something is you. So, right now you need to grieve, and you need to get through it."
When she was just 2 weeks old, Katherine began seeing Colleen Coulter.
"Here at Children's, the families come immediately into our program," Coulter says. "Right before you came, I saw a 27-day-old baby."
In order to fit Katherine with an artificial leg, the team had to wait until she was able to pull herself up on her own.
At about 9 months, they created a foot-on-foot prosthetic.
"A lot of kids revolt when you put a prosthesis on them, because it slows them down," Coulter says. "This one, she likes it. She really likes to wear it."
But teaching a toddler to walk while balancing on a new leg has been challenging.
"It's still frustrating because she is still not walking independently," Mary Heath says. "And, sometimes, she gets frustrated, and she gets tired of wearing it, because it does make life more difficult when she has it on."
As Katherine grows, she returns to Children's each month, so the prosthesis can be tweaked.
Children's prosthetist Rebecca Hernandez knows Katherine's journey well.
She too, was born with PFFD, and she wears a prosthesis.
"Growing up with PFFD has definitely led me to my life's work," Hernandez says, as she adjusts Katherine's prosthesis.
"So, I take great pride in watching these kids grow and become as active as possible."
Mary Heath says the surgeon was right: Katherine will do things her own way, on her own time.
"She's going to figure it out," her mother says. "As soon as I start questioning whether she will or not, she gets it.
She's just amazing."