Learning about Congenital Melanocytic Naevus (CMN) Syndrome
Genetic Disorders CMN syndrome is a rare disease where children are born with extensive birthmarks covering up to 80 per cent of the body surface.
In its severe forms it occurs in around 1 in 20,000 of all births all across the world, which equates to approximately 500,000 people affected worldwide at any one time.
These birthmarks can be accompanied by neurological abnormalities, although most children have normal intelligence and go to mainstream schools. The birthmarks also confer a predisposition to the most devastating form of skin cancer, melanoma. If melanoma develops it is usually in childhood, and thus far is untreatable. Children are therefore under regular surveillance and they and their families have to learn to cope with the threat of this possible complication.
This disease can affect anyone, as it is not inherited in families, and it is not picked up on ante-natal screening tests so is always a shock to parents. It is currently untreatable. Doctors in the UK are leading research on this condition, and discovered recently that it comes about as the result of a chance genetic mutation in the baby very early in pregnancy. The gene turned out to be a known melanoma gene, which explains the risk of cancer. This finding has now led to early research into using gene therapy to reverse the skin changes after birth. This research is being funded by Caring Matters Now charity and patient support group.