Chart-topping musician Mason, whose real name is Iason Chronis, has revealed how he was left partially paralysed overnight by a rare autoimmune disease. Now, the 46-year-old is fighting fit and preparing to take on a gruelling 100-kilometre ultra-marathon from London to Brighton to raise funds for Inflammatory Neuropathies UK.
A Sudden Collapse
In 2019, the Amsterdam-born artist was at the peak of his career, performing in front of thousands of fans each night. But without warning, he began collapsing. Within days, his condition deteriorated rapidly. He was diagnosed with Guillain-Barré Syndrome (GBS), a rare disorder in which the immune system attacks the nerves, causing muscle weakness and often paralysis. GBS affects only 1 to 2 people per 100,000 worldwide each year.
Speaking from his studio in his first interview about the condition, Iason said: "I was partially paralysed and couldn't walk or anything; it happened overnight. I was DJ'ing in Taiwan and all of a sudden I started to collapse a few times, and then in a few days it got worse." He recalled how his legs could not hold his weight: "It was really strange. I felt my legs couldn't hold my weight."
The Road to Recovery
Iason suffered for two years before recovering. He set a goal to run again, starting with slow jogs to the end of his street. "For me, running was a logical step in recovery. I couldn't walk to the end of the street, so I ran slowly to the first mile," he explained. The COVID-19 lockdown inadvertently helped, as he did not have to cancel shows. "I was just recovering; the whole period was a bit of a blur," he added.
Medics initially feared more severe conditions such as ALS or a spinal tumour. "They were looking at bigger things first, like ALS or maybe if I had a tumour on my spine. These were kind of scary scenarios," he said. Fortunately, he stabilised after a few weeks and was sent home to recover. "Mentally, I was fine; I could write music," he noted.
The Ultra-Marathon Challenge
Now fully recovered, Iason is taking on a 100km ultra-marathon from London to Brighton, finishing at the Brighton Music Conference. Despite a forecast of 29°C heat, he remains determined. "I've done 60 marathons in my life; this is an extra marathon, but in theory it should be fine," he said with a laugh.
He is raising money for Inflammatory Neuropathies UK, a charity close to his heart. "I have no idea how it's going to be. I have a friend pacing me, who's coming halfway, and the cool thing is finishing at Brighton Music Conference," he added.
A Career of Resilience
Twenty-five years into his career, Iason reflects on his journey. His breakout hit, Perfect (Exceeder), released in 2007, was originally a B-side. The track gained a new lease of life after being featured in the film Saltburn, going viral on TikTok. "18-year-old TikTok followers had no idea or might not have known the song," he laughed. The resurgence led to remixes by David Guetta and Jax Jones.
Iason approaches music with a focus on personal fulfilment. "I think to really focus on process and the fulfilment of creating the music I want to be making and not feeling pressure from industry or peers," he said. "At the end of the day, it needs to be my journey where I'm fulfilling myself."



