A toddler from the U.K. is believed to be the only person in the world to be diagnosed with an extra strand of DNA – a condition so rare, doctors don’t even have a name for it.

Alfie Clamp, from Warwickshire in northern England, has an “extra arm” on his seventh chromosome.

Doctor discovered the extremely rare condition when Alfie, who was born blind and with severe disabilities, was just 6 weeks old.

A series of tests revealed the extra strand of DNA, which has left the medical world baffled. Doctors have no idea what his life expectancy will be or whether his condition will even improve.

The 2-year-old has digestive problems, needs drugs to help his body absorb nutrients and suffers spasms brought on by high temperatures and metabolic problems.

But his parents said despite his ordeal, their son means the world to them, and they are now concentrating on the simple things, the Daily Mail reported.

“When the doctors told us I was absolutely devastated,” Alfie’s mom, Gemma, said. “As a pregnant woman, you spend nine months thinking about what it will be like when your baby takes their first step or claps their hands. Having a boy like Alfie makes you appreciate the little things. He didn't roll over until he was 18 months old, but we were so excited when he did.”

Click here to read more about Alfie and see a picture of him at the Daily Mail.