By Joe Roberts @jrobertsjourno
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Videographer / director: Edward Sanchez
Producer: Joe Roberts, Ruby Coote
Editor: Beth Angus
Sierra and Sienna Bernal, 20, are identical twin sisters but were born with a significant difference: Sienna has Primordial Dwarfism.
The condition causes small body size, resulting in Sienna being more than a foot smaller than Sierra, and weighing only 50 pounds, in comparison to Sierra’s 98 pounds.
Sierra told Barcroft TV: “Sometimes whenever people find out we're twins they’ll ask ‘how old is she?’ So a lot of times even after you've established that we’re twins they'll ask Sienna if she's younger.
“I’m like ‘that’s how twins work, we’re the exact same age’. And even sometimes people think she’s my daughter.”
Sienna, who weighed just one pound seven ounces at birth, added: “People do often think I'm younger than my age. They think Sierra is my older sister and they treat me differently.
“When they talk to me like a kid they'll be like ‘how are you?’ I’m like ‘I am fine. I am 20 years old. And I'm an adult. I’m not a kid.’”
The girls say they might be the only instance in the world of identical twin sisters where one has Primordial Dwarfism.
What’s more, Sienna has a form of the condition which doctors are yet to classify, having not yet discovered it in anyone else.
“I have a form of Primordial Dwarfism that they haven’t discovered yet,” said Sienna. “So they're thinking I might be my own kind of dwarfism. They don't know. the doctors are still trying to figure it out.”
Sienna was also born with Dandy Walker syndrome, which causes abnormal brain growth.
Dad, Joey, explained: “Sienna has Agenesis of Corpus Callosum, which is the membrane that separates the left and right hemisphere of your brain.
“Essentially, what that means is it's not completely there; it's kind of reduced. And while they expected the Dandy-Walker to cause Sienna to be a vegetable, we think that somehow or another her brain found a way to rewire itself.”
Despite these major physical differences, the sisters are just as close as any other identical twins, sharing a unique bond and supporting each other through everything.
Sierra said: “I’m extremely protective over my sister, which I think has made her a little sassier because she knows Sierra is going to take care of it if there's a problem.
“I remember when we were really young, I think I was five years old. There was this girl. She was four years older than us and she was bullying Sienna at the playground because she was smaller.
“I don't really see why that would be a reason to bully her, but it was. She didn't want Sienna to play with her and she was calling her names and being mean to her.
“I may or may not have got in trouble with the principal because I punched her in the face. But you know what? She didn't bully her anymore. So I say problem solved.”
It’s been a remarkable journey for Sierra and Sienna, considering mum Chrissy wasn’t even expecting twins until a few weeks before their birth
“Sienna was so little that she didn't come up in any of the previous tests,” said Chrissy. “Three weeks before they were born that they said, ‘you've got two in there’.
“I had to quickly get over that shock though, because that was when they immediately said that ‘baby B’ has some medical concerns.”
On top of the shock of finding out she was having twins and that there were potential issues with the newly-identified baby, Chrissy was given a sobering prognosis at the twins’ birth.
“When Sienna was born, they actually said she would probably not make it past 24 hours. We got told that a lot.
“Then they said if she did survive, which they gave her a 10 percent chance of making it out the hospital, they said she would most likely be a vegetable.
“So that’s what they told me. They told me to prepare for that, and I said ‘well you don’t know what God has planned’.”
Not only did Sienna survive, she and her sister thrived in the coming years, and now Sienna is writing a book, and recently started college while Sierra is an accomplished singer and songwriter.
Seeing the close bond the twins have developed, It’s hard to imagine that Sienna was given such small odds of surviving in the beginning.
Chrissy, said: “They have the sibling bond, like normal siblings do, but with being twins, they're definitely closer.
“You can see it if they've been separated during the day, they will immediately come together, and you can tell they really did not like not being together.”
Dad, Joey, added: “While they both have their own room, there are so many nights they will fall asleep watching movies together. It's just one of the things they do, they're stuck together.”
Now, the soon to be 21-year-old sisters continue to inspire their parents, with Sierra’s music career gaining momentum, and Sienna accomplishing things that seemed so unlikely at her birth.
“I used to do cheerleading and I used to dance,” said Sienna. “I couldn't do it anymore. I was like ‘okay, you’re past your limit now, time to stop. So now, I swim a ton.
“I actually learned how to swim twice because my twin sister taught me how to swim the first time and then she taught me how to swim again because I forgot.”
Sienna is also passionate about mermaids and can often be found swimming wearing one of her mermaid tails.
“I like mermaids because they are super unique and different,” she said. “They live in two worlds. They’ve got the human and the fish, so that’s kind of the best of both.”
In the future, Sierra hopes to continue her success in the music industry, while Sienna is looking to graduate college, publish her book, and even start a career as a mermaid.
“I tell people ‘follow your heart and what your heart tells you’,” said Sienna. “Listen to what your music is telling you. That’s what I'm trying now; I’m trying to follow where my heart leads me.”
Whatever the twins do, they can count on their parents, who remain incredibly proud of their girls, to support them.
“I've never been more proud,” said Joey. “To see some of the things they had to deal with growing up, and to be where they are individually, on their own, is a really big deal.
“For Sierra, to be a female in country music, you don't just have to be tenacious, you have to be fearless. And you have to be willing to go above and beyond, so she's constantly setting that bar higher.
“And there were people that said certain things couldn't happen for Sienna, but yet at every corner, she proves them wrong.
“She has days when she's literally said to me ‘Dad, why did God make me so small?’ And I just say ‘maybe if he made you full-size you’d try to take over the world.’