Wednesday, March 21 marks World Down Syndrome Day. It's celebrated on the 21st day of the third month to signify the uniqueness of the triplication of the 21st chromosome which causes Down Syndrome.

While it's a day to celebrate the gene it can also be the day to celebrate overcoming challenges.

Ashlee and Forest Persings have a four-year-old daughter, Brighton, with Down Syndrome.

Forest says the hardest part was finding out the diagnoses in the beginning.

"Really the fear of not knowing what to be expected..." He said.

They say Brighton does not suffer from hearing, vision, or heart issues that can come with Down Syndrome. What she does have is low muscle tone.

"One of the most common things with Down Syndrome is low muscle tone which causes a weakness. It makes it more difficult to learn gross motor skills like sitting up and crawling and walking, and so at 10 months old Brighton started to get physical therapy."

Other therapies were also needed to help with eating skills and Brighton's speech.

One of the challenges they face is when Brighton gets sick.

"Something that my son would pass through in about two or three days she would take a week or two weeks to get through." Forest said.

In her younger years she would get infections and have sinus problems.

"It was just hard because everything inside of her, her sinuses, everything inside were so much smaller." Ashlee said.

The lack of muscle tone also made it hard for Brighton to cough something out of her system.

The Persings say Down Syndrome is not considered a challenge, for them it's a way of life. They describe Brighton as silly, fun, compassionate, not to mention she loves messing with her big brother.

Her parents goal is to one day have her in a mainstream classroom and to be fully included into society.

Watch the full interview here:

Kathleen Bullock has daughter, Tori, who has Down Syndrome.

They've faced some of the same challenges as the Persings but they also have some of their own.

Bullock mentioned it can be hard in society with people staring or automatically jumping to conclusions.

"Sometimes she's not accepted with her peers you know, doesn't get all the invites to the birthday parties." she said.

She works hard to make sure Tori gets the social interactions she needs.

They believed Tori suffered from hearing issues. They went to the doctor in Longview, and then they had to go to Dallas and a few other steps that make the process even longer.

"Phone call after phone call. You know, two hour drive to Dallas just to get hearing tests, to get the kind of help you need, the tubes in their ears. It just kind of grows, and grows, and grows and you keep on telling yourself 'Why does this take so long? Why do we have to go through so much just to get the things we need?'"

For years Tori was sick and throwing up every day. Now they know it was due to Celiac Disease, but it took over a year of testing, doctors' visits, emergency room visits, and one unnecessary surgery to remove her Gall bladder before they realized Tori is allergic to gluten.

Through those hard times there were good times too.

One of Bullocks favorite moments was when ,after two-and-a-half years, Tori finally walked.

"She had such a desire to do it(walk) but it took so much muscle tone and so much strength to finally get there... I mean, now she runs!"

Currently Tori is a Girl Scout, a cheerleader, she is in equine therapy, and participates in the Special Olympics.

Both families believe it doesn't matter what disability or special need someone has, they can still achieve big things.

Watch the full interview with Kathleen Bullock here:

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