Genes may be as important as diet and dental hygiene in the development of gum disease, research shows.

An international team of researchers has discovered that changes in a gene for the enzyme, cathepsin C, are responsible for a condition known as Papillon-Lefevre syndrome.

Among the symptoms of this syndrome is inflammation of the gums (gingivitis).

Cathepsin C, which is found in skin and bone cells, activates several of the chemicals controlling local immune and inflammatory responses.

Researchers have now identified that different mutations of this same gene are responsible for another condition, prepubertal periodontitis.

This is a severe form of gum disease that develops early in life, and progresses very rapidly.

The researchers studied 14 members of an extended Jordanian family.

Four children with evidence of gum disease had mutations in both copies of their cathepsin genes.

Relatives who only had one copy of the mutated gene seemed to be protected from developing severe gum disease.

The authors say the findings indicate functioning of the cathepsin C gene is needed for healthy gums.

Up to one in five adults may develop some form of periodontitis. The researchers are now trying to establish whether the same gene mutation is linked to other forms of the disease.

The researchers believe the function of the gene may be influenced by other factors such as diet and exposure to bacteria.

But they think it is the gene itself that determines who is at risk of developing severe gum disease.

Professor Tom Hart, of the University of Pittsburgh, said the discovery could eventually lead to new treatments.

He said: "Severe, early onset gum disease will probably be preventable in the future."

Professor Hart said once those at risk were identified they could be targeted for regular cleaning of the gums, and potentially given anti-inflammatory pills and top ups of cathepsin C.

The research was published in the Journal of Medical Genetics.