“We’re on edge all the time,” Siobhan Smith said after her son Rupert was diagnosed with alternating hemiplegia of childhood (AHC)

An infant was diagnosed with an incurable “one-in-a-million” neurological condition after his parents noticed one minor sign.

David and Siobhan Smith — a couple from North Wales, England — welcomed a baby boy, Rupert, in May 2025. He was seemingly born healthy, aside from minor breathing difficulties. However, a couple of weeks after his birth, he started experiencing unusual symptoms, including a “flicker” of his eyes.

“At about two weeks old we noticed his eyes were flickering side to side, up and down, then they’d lock to one side, so we had him tested for neuroblastoma but that came back okay,” David, 40, told Southwest News Service. “Then he started having rigid episodes where his whole body would tense up, along with the eye movements, which they thought was epilepsy but those tests were normal.”

Despite extensive testing coming back normal, Rupert was still experiencing symptoms. When he was 6 months old, he suffered a near-death episode where Siobhan had to perform CPR to resuscitate him.

Rupert was transported to the hospital and genetic testing led to him being diagnosed with alternating hemiplegia of childhood (AHC) in January 2026.

Alternating hemiplegia of childhood (AHC) is a rare neurological disorder resulting from a gene mutation. It causes repeated episodes of weakness or paralysis and can be triggered by anything, from environmental conditions like temperature or bright lights to loud noises or emotional disturbances. As of now, there is no known treatment or cure.

Rupert now requires nonstop care to manage his episodes of paralysis, seizures and serious medical emergencies. He’s since had two major episodes at 8 and 11 months old.

“We’re on edge all the time. You can’t take your eyes off him at all,” Siobhan, 36, told the outlet. “It’s very unpredictable. One minute he can be smiling, next minute he’s having a life-threatening seizure.”

“It’s not something Dave or me carry, it’s just a misspelling in his genes,” she continued. “Episodes are triggered by stress on the body; if he’s tired, hungry, too excited, too hot, cold, exposed to water. Even going outside can cause a seizure.”

Rupert is currently in the care of neurology, respiratory, cardiology, physiotherapy, speech and language, dietetic, hospice and community nurse care at two different hospitals.

“This last set of seizures — over 48 hours he probably had 12 — was triggered we think by teething,” Siobhan said. “Something as little as that can cause a significant event. We have his oxygen, rescue medications with us everywhere we go.”

“We can’t allow him to become too excited, too upset or too happy because that can trigger something,” she added. “To not allow your child to be too happy is really hard to take. But he’s still so smiley, and so determined.”

Ahead of Rupert’s first birthday on May 28, David and Siobhan are raising money to travel to the United States for potential treatments. They have since raised over $350K, and said any extra will be donated to foundations created to fund research into cures and treatments for the condition.

“Time is critical. We’re hoping treatment comes through in 12 months, and a cure hopefully in a couple of years,” Siobhan said. “We’re hopeful.”

“We’d do anything for him. He’s beautiful, everyone who meets him falls in love with him. That’s why we’ve got so much support, everyone wants to do what they can to help because he’s so resilient,” David said. “But there’s only so much you can take, he’s had to deal with more than most people do in their life, and he’s not even one yet.”