Twins often don't look that much alike, but Sienna and Sierra Bernal’s situation is quite different. At the age of 21, these two sisters from Tomball, Texas have major differences, and the one that jumps out at you is their size. Sierra is almost twice the size of Sienna. When you look at the two young women, you may wonder if they are actually twins. In reality, Sienna was born with primordial dwarfism.
What is primordial dwarfism?
This is a disease that affects a very small percentage of the population. It is estimated that there are only 200 people with this syndrome. The syndrome results in significantly stunted growth. Affected individuals have limbs in proportion to their size, but this is significantly reduced. In general, they stop growing when they reach around one metre.
The twins arrived six weeks early. Sienna was not fully developed when she was born, unlike her sister. It wasn't until she was about six years old that she was diagnosed because until then she seemed to grow at a slow but normal rate. She also developed Dandy-Walker Syndrome which causes abnormal brain growth.
While primordial dwarfism is a rare condition, Sienna and Sierra's situation is unprecedented. This is the first time that the syndrome has affected a single person in a pair of twins, and this is something doctors can't explain.
A daily struggle
Of course, the disease can be complicated for Sienna to manage. But she can rely on her sister who is always there for her:
Every time people find out that we are twins, they ask how old Sienna is. So often, even after explaining that we are twins, they keep asking Sienna if she is younger. So I say, 'That's how twins work - we are exactly the same age.'
Sienna doesn’t hesitate to speak out either!
Sometimes they think Sierra is my big sister and they treat me differently. I am not a child. Let's be clear about that. When they talk to me as if I were a child and they ask me how I am, I say: 'I am fine, I am 20 years old.'