Doctors have used a new type of medicine called "gene silencing" to reverse a disease that leaves people in crippling pain.

Axar.az reports ciitng BBC.

The condition, acute intermittent porphyria, also causes paralysis and is fatal in some cases.

The novel approach fine-tunes the genetic instructions locked in our DNA.

Doctors say they are "genuinely surprised" how successful it is and that the same approach could be used in previously untreatable diseases.

What is porphyria?

There are several types of porphyria, but each is caused by the body being unable to produce enough of a substance called haem.

Haem is a key component of the haemoglobin in red blood cells that transport oxygen around the body.

Problems in the body's haem manufacturing process can lead to a build up of toxic proteins.

These cause the attacks of physical pain in Sue's form of the disease. In other porphyrias the proteins can cause skin problems.

There is some speculation King George III had porphyria.