A boy with untreatable wounds has had 80 percent of his skin replaced with a genetically modified epidermis in an attempt to save his life.

The 7-year-old boy has a life-threatening genetic disorder that has caused untreatable and infected wounds all over his body. Before the surgery to replace it, the Syrian boy, named only as Hassan, had lost around 80 percent of his skin to the disorder. In 2015, he was admitted to a children's hospital in Germany where the doctors tried to make him comfortable after all other attempts to heal him had failed.

The condition he suffers from is called epidermolysis bullosa (EB), a rare inherited skin disorder. Sufferers have genetic mutations on one of three genes, LAMC2, LAMA3 or LAMB3, which help produce the laminin 332 protein. This protein is what helps attach the upper layers of skin to deeper layers. As a result of the mutation, sufferers' skin can become blistered from just a mild bump or friction. 

The study, published recently in Nature, reports Hassan suffers from junctional epidermolysis bullosa, which accounts for around 5 percent of EB. Considered to be one of the most severe forms of the condition, sufferers can have trouble eating as blistering can also occur within the body. Around 40 percent of children with the condition won't survive their first year, and most don't live past five.

So the doctors were up against extreme odds when they attempted to repair the boy's skin using a genetically modified replacement. Researchers from the University of Modena and Reggio Emilia in Italy took stem cells from a small patch of unblistered skin from the boy's groin region and used this to grow new skin in the lab. Before growing sheets of skin from the cells, the team used a retrovirus to insert a healthy, non-mutated version of the LAMB3 gene.

The surgeons spent two months grafting the skin grown in their labs onto the boy. He spent months recovering, covered in bandages, before he was let out of hospital in February 2016.

“The kid is now back to school. He plays soccer,” lead author Dr Tobias Hirsch, from the hospital, told BBC News. Almost two years later, Hassan is doing well. He doesn't need to take medicine, is doing well at his school in Germany, and his skin heals just like other healthy children.

Professor  Michele De Luca, who led the study, told the BBC that she wants to further study how effective treatment would be on other types of EB.

"The gene is different, the protein is different and the outcome may be different [for each form of EB] so we need formal clinical trials."