For the first year of her daughter’s life, Lainey Moseley was in denial.
“I knew in my gut things were wrong,” Moseley, 51, of Philadelphia tells PEOPLE. “Leta’s head was floppy; she wasn’t sitting much at six months; she wasn’t putting on weight. She still looked like a 3-month-old at 8 months old. At a year she wasn’t talking.”
But she kept telling herself Leta would outgrow it.
“You don’t ever give up hope,” she says. “I was like, ‘She’ll be like Einstein. She’ll talk when she’s ready.’ ”
When Leta was about a year old, after she’d been having trouble breathing, her mother took her to a doctor who said he thought the little girl had Cornelia de Lange syndrome, a genetic disorder.
“I was devastated,” she says. “What are the symptoms? Severe retardation, and they don’t know life expectancy.”
“We didn’t think she had Cornelia de Lange syndrome, but we didn’t know what she had,” Krantz tells PEOPLE.
That started Leta and her family on a medical odyssey that would take more than ten years – and require some dramatic technological advancements in medicine – before they got any answers.
“Once I realized she wasn’t developing and not meeting milestones and needing oxygen and heart surgery and getting worse and worse and worse, I quit working,” says Lainey, who at the time was married to Rick, 54, who works for a finance company.
“I was crazy enough to have two more kids, and those pregnancies were like playing Russian roulette, because I honestly didn’t know if I was going to have another child with the same genetic syndrome,” she says. “I just prayed they were going to be healthy.”
Meanwhile, the Moseleys had a very sick child on their hands.
Not only did Leta look different than other children – even now, at 17, she’s only 3 ft. 6 in. and weighs 65 lbs. – but she was nonverbal and had life-threatening lung problems that routinely landed her in the hospital for months at a time.
“Leta almost died a couple of times,” says Lainey, a freelance writer and TV news producer. “The stress when your child is sick permanently changes you. You are forever affected by the posttraumatic stress of that experience. You just don’t see any light at the end of the tunnel. It used to be a revolving door. We probably spend two or three months a year at CHOP.”
And no one could tell them what was wrong.
“It’s incredibly unsatisfying to have her undiagnosed with people scratching their heads and saying, ‘Hmm. There’s something unusual about that child,’ ” says Moseley.
Dr. Krantz didn’t stop searching for answers.
“In genetics we call that the diagnostic odyssey – looking and looking and looking,” he says. “I took Leta’s photo to conferences and presented her case to doctors from around the country. We were desperate to find an answer for the Moseleys. It’s frustrating not to be able to give a family a definitive answer.”
When Kathleen Hilferty had twins on Aug. 2, 2000, they were about the same size.
Joe weighed 7 lbs., 6 oz., and Liam weighed 5 lbs., 10 oz.
Once she got them home, it wasn’t long before it became apparent something was wrong with Liam, she says.
“He aspirated some milk and wouldn’t breastfeed,” Hilferty, 46, of West Chester, Pennsylvania, tells PEOPLE. “He was having problems breathing.”
By Christmas, he was hospitalized, and a tracheostomy was inserted to help him breathe.
“It was March before he came home,” says Kathleen. “He was still very floppy. They’d diagnosed him with chronic airway disease, but I knew something else was wrong – not just the airway.”
Liam, who also had a hole in his heart, kept the trach in for another two and a half years. Kathleen even temporarily moved to Ohio so Liam could see a specialist there who agreed to do reconstructive airway surgery on him.
“We almost lost him a few times,” she says.
“It was very heartbreaking at times – not knowing what may take your son,” she says. “I kept wondering, is there a magic pill, a magic treatment? I wanted so much to have a diagnosis – at least to have a name. We were calling what he had ‘Liam’s syndrome.’ ”
Doctors thought he’d die many times over the years, she says.
“As bad as his lungs are, his GI issues were worse,” she says. “They said the next respiratory infection could take him. He’s like a ticking time bomb.”
And they told her he was terminal.
“I’m like, ‘How do you know if you don’t know what he has?’ she says. “They said, ‘Because his lungs and heart are not in great shape.’ ”
Liam landed in the care of Dr. Krantz in 2008.
“I thought, ‘He looks just like Leta,’ ” says Dr. Krantz.
He had the same small stature, similar facial features and similar health problems. Though he was also nonverbal, he communicated through sign language.
Meanwhile, Melissa Ashton-Grant, now 34, and her husband, Levar, now 35, of Brooklyn were in the midst of their own agonizing medical odyssey.
Melissa gave birth to Nadira in March 2004. She was just three pounds, 14 ounces and 17 inches long but she was also six weeks premature so doctors told her not to worry.
“They said for a baby that was born at 33 weeks the weight was appropriate,” she tells PEOPLE.
A month after she took her home, Nadira started getting badly congested.
“Everytime I’d take her back to her high risk appointments they told me, ‘No. It’s fine,’ ” says Melissa, who works in social services. “It’s probably just a little virus. It’ll blow over’ ”
Then that June she was feeding her one night when her mother noticed something was wrong.
“I burped her and my mom said, ‘Melissa, is the baby sleeping?’ she says. “I said, ‘She shouldn’t be.’ She said, ‘Something doesn’t look right.’ So I turned her around and realized she wasn’t breathing. After stimulating her I heard her gasp for air and immediately rushed her to the hospital.”
Nadira ended up staying there for four months and had a tracheostomy inserted to help her breathe. The next few years were rough. At one point Nadira had to be fed with a feeding tube and she was admitted into a rehab facility.
One doctor finally recommended she take Nadira to Dr. Krantz, who had helped discover the gene that caused Cornelia de Lange Syndrome, which she thought she might have.
“I said, ‘No problem because I’d love to know what she might have,’ says Melissa. “I was scared to have another child.”
And not knowing what caused her child’s illness was scary, she says.
“I realized some people were under the impreesion I’d done something wrong and this is why she is the way she is,” she says. “So that was really hard. At one point I was blaming myself – for what I don’t even know.”
And it was hard seeing friends and family with their healthy babies, she says.
“I was really depressed,” she says. “But I had to just tell myself this is what the situation is.”
Dr. Krantz tested for the disorder and was able to rule it out but for him, though he had thousands of other cases, that’s when the pieces started to fall into place.
“I was convinced all three [Leta, Liam and Nadria] had the same diagnosis, but we had no real approach to finding out what that was until some of the new technology allowed us to screen all of their genes,” he says.
In January 2012, a new form of enhanced DNA testing called whole exome sequencing became available, so he decided to compare the DNA of all three kids and see what he could find.
“When he came to us and said, ‘I have these two other kids, and I think you share a diagnosis, so I want to get a blood sample from Leta,’ I just sort of rolled my eyes and said, ‘Yeah, go ahead,’ ” says Lainey. “I appreciated his doggedness, but then I completely forgot about it.”
In February 2013 Dr. Krantz called.
He finally had an answer.
To find out how Dr. Krantz solved this medical mystery, check out People.com Sunday.