Teenager with autism runs 3:57 mile and sets T20 world record

New Paralympic World Record just went down in Raleigh tonight! Congrats to @mikeybrannigan for going sub-4 and making history! #sirwaltermiler #miler16 #bringbackthemile #track #run #running #runlocal #raleigh

A photo posted by Michelle Ames (@traz5) on Aug 5, 2016 at 7:19pm PDT

Rio-bound Paralympian Mikey Brannigan set a T20 world record in the men’s mile (1,609m) on Friday evening in Raleigh, N.C. at Sir Walter Miler. The 19-year-old, who was diagnosed with autism when he was 18-months-old, ran 3:57.58 and broke the 4:00 barrier for the first time.

RELATED: Speedy 85-year-old Canadian Ed Whitlock breaks 5,000m world record.

Brannigan, 19, runs for New York Athletic Club (NYAC). He competes in the T20 classification, a category for athletes with intellectual disabilities, and will represent the United States at the Paralympics in September. Brannigan won the men’s 1,500m at the Parapan Am Games in Toronto last summer.

From tonight's Sir Walter Miler. 1 World Record, 2 State Records and a new PR for Graham Crawford #miler16 pic.twitter.com/YJfiU81Y5B

— Pack Track & Field (@Wolfpack_TF) August 6, 2016

Autism is a brain development disorder characterized by impairment of social interaction, both verbal and non-verbal, as well as repetitive behaviour.

On Friday, Brannigan finished just behind high school star Drew Hunter, who recently signed a 10-year professional contract with Adidas. The winning time was 3:54 by Kyle Merber. According to Flotrack, Brannigan’s 3:57 was a six-second improvement on his previous best.

Congrats @MikeyBrannigan on a 3:57.58 mile! You're an inspiration to all athletes w #autism! Good luck @Paralympics pic.twitter.com/kYywLyqtVD

— Shannon Leinert, PhD (@ShannonLeinert) August 6, 2016

Brannigan already owns the T20 world record in the men’s 1,500m (3:48.85). He’s the world champion in the men’s 1,500m. The mile, just over four laps of a 400m track, is run less often than the 1,500m, especially in Canada, though it’s still considered a popular event because of its rich history. A four-minute-mile is the benchmark for men.

RELATED: Canadian Corey Bellemore lowers beer mile world record to an incredible 4:34.

When in high school, Brannigan attracted interest from top-tier universities and colleges across the United States but did not gain admission because of having to write standardized tests. He attends Suffolk County Community College in Selden, N.Y. He’s a favourite to win gold in the middle distance event at the 2016 Paralympic Games.

Brannigan was profiled in a 14-minute episode of ESPN’s E:60 in December. As a child, Brannigan always had plenty of energy and didn’t begin speaking until he was four. His family enrolled him in a running program shortly after and he has been a running phenom throughout high school and now as a NYAC athlete.

Rachel Cliff was the only Canadian in the mile races and finished 12th in 4:38.39.