Triathlete to raise funds for brother with rare Down syndrome disorder

Johnny Byrne is dedicating his triathlon training to raising funds for a rare Down syndrome disorder that his brother Thomas suffers from. Photo by Nadia Bidarian

by Nadia Bidarian

Johnny Byrne, 22, was spending his summer juggling a business internship and classes at UC Berkeley when he decided to add training for the 70.3 mile Santa Cruz Triathlon to his schedule. The Manhattan Beach resident’s motivation to do the triathlon was to raise research funds for Down syndrome disintegrative disorder (DSDD), a rare disease that causes individuals with Down syndrome to regress in their language and other skills. Byrne’s younger brother Thomas suffers from the disorder.

After learning how little is known about DSDD, Byrne decided to dedicate the triathlon he was training for to raise research funds for the disease. In May, Byrne created a fundraising page on the IronMan Foundation website, and since then, he has raised over $31,000 of his $50,000 fundraising goal. The Santa Cruz IronMan is September 12.

“I never thought I was going to do this. But my brother was going through a really hard time, and I thought it was a great way to showcase the power of community support within the local beach cities and to raise awareness about DSDD, a disease that gets no attention,” Byrne said. 

Down syndrome is the most common chromosomal condition in the U.S., occurring in one of every 700 babies. Individuals with Down syndrome are born with one extra chromosome, leading to intellectual disabilities and other challenges.

In Thomas’ case, Down syndrome has not stopped him from being athletic, as he played basketball, and football, and he swam. Nor was he shy. “He always had a smile on his face, and he gave big hugs to everybody,” Byrne said. 

Thomas worked hard to progress both academically and socially.

“There are things people who don’t really fit into the mold can teach us that really aren’t easy to see on the surface. Some of the qualities are gratitude, love, perseverance, and kindness,” Byrne  said. “I can say with pure authenticity that Tom genuinely has the biggest heart that I’ve ever seen.”

While DSDD only occurs in individuals with Down syndrome, it is much rarer than Down syndrome itself. DSDD causes individuals to lose previously acquired adaptive, cognitive, and social skills, typically over the course of only a few weeks. Muscle stiffness, insomnia, and language loss — either speaking in whispers or not at all — are other common symptoms. Oftentimes, it is difficult to pinpoint the trigger. 

Thomas’s DSDD was brought on by autoimmune encephalitis, which he was diagnosed with in 2000 and led to inflammation in the brain. He found himself uninterested in activities that previously brought great pleasure, like exercise. 

“Thomas is a lovely guy, and I think that it’s hard to see somebody who is as bright, energetic, lovely, and empathetic as he had been in the state that he was in,” said Jonathan Santoro, a neurologist leading research into DSDD at the Children’s Hospital Los Angeles (CHLA). “This isn’t just some random psychiatric condition. This isn’t just depression. This isn’t just Down syndrome. This is its own thing.” 

Byrne’s triathlon sponsorship funds will go directly to Dr. Santoro and his team. Although DSDD was researched briefly in 1946, its rarity and its tendency to be simply “chalked up as part of Down syndrome,” according to Santoro, led to a lack of research into the disorder. By working with patients like Thomas, Dr. Santoro’s team wants to change that.

“The goal is to find out what is causing DSDD and fix it,” Dr. Santoro said. “Only about one-third of patients so far have been identified as having inflammation in the brain. We want to know if there is another genetic or metabolic cause that may be treatable.” 

It was only two years ago when CHLA began evaluating patients with DSDD, and not long after that when Thomas began seeing Dr. Santoro. Dr. Santoro identified numerous unknowns in DSDD research: what exactly causes DSDD; which patients need immunotherapy, which need supportive therapy, and which need both; and whether the treatment will be ongoing or eventually conclude. 

“Johnny sent me an email and he said, ‘I want to help out with this.’ I was excited, but I didn’t know what that would mean. I thought it would be like $1,000 to help pay for some lab testing,” Dr. Santoro said. “When I looked online to see how much he was raising, I couldn’t even believe it. What Johnny is doing is going to jumpstart a research revolution into this condition.”

Byrne trains twice every day, usually at The Yard in Hermosa Beach. The first training is always cardio, such as a bike ride, swim, or run, and the second is either weights or more cardio. 

“It is pretty grueling,” Byrne said. “I played volleyball in high school, but this is by far the biggest physical goal that I’ve ever gone after.” 

Byrne plans to host a fundraiser in August, one month before his triathlon. Videos of kids whom Thomas grew up with will be played, each sharing stories of how he impacted their lives. Byrne said he’s seen “a great amount of support” from the Beach Cities, as well as from American Martyrs School in Manhattan Beach, where Thomas attended for Pre-K through 8th grade, and Cathedral Catholic High School in San Diego, where he attended from 9th to 12th grade. 

“I don’t think I would have values like generosity or compassion or empathy in my character if it wasn’t for Thomas and his ability to teach me those things,” Byrne said. “This whole situation shows just how impactful people with mental disabilities can be and just how many lives they touch.” 

To donate, visit and enter “Johnny Byrne” into the search bar. ER


comments so far. Comments posted to may be reprinted in the Easy Reader print edition, which is published each Thursday.

Be an Easy Reader Free Press supporter!

Yes, we know Easy Reader and are free. But they are not free to produce. The advertiser model that traditionally supported newspapers is fading away. This is our way of transitioning to a future where newspapers are supported by their readers. Which is as it should be. We hope you’ll support us. — Kevin Cody, Publisher