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The Congenital Nevus Support Group©


The cause of congenital moles may have recently been discovered! Researchers have known that the skin and nerves of a fetus develop from the same primary cells of the body, which are called neuroectodermal cells, between the 8th and 24th week of pregnancy.   Researchers think that a body protein called HGF/SF (hepatocyte growth factor/scatter factor) seems to be responsible for encouraging these neuroectodermal cells to develop, migrate, and "scatter." In those of us with a nevus, it seems that we have too much/wrong type of this body protein scatter factor in some, not all, of our cells, so we develop extra pigment and abnormal skin cells called nevus cells. We may also have too much/wrong type of the receptor for this scatter factor, a body protein called C-met. These primary nerve/skin cells are told to "scatter" around by scatter factor, so we have nevi "scattered" all over us. If we have lots of nevus cells scattered on the skin, there seems to be a good chance that we have the same cells scattered in the brain. That may be why some of us develop nerve symptoms like hydrocephalus, "water on the brain," meningeal melanoma, "skin cancer in the brain", and neurocutaneous melanosis, "nevus cells in the brain." A Japanese researcher recently developed mice with too much/wrong type of the body protein HGF/SF. Guess what? The mice developed giant pigmented nevi with satellites! Isn't THAT fascinating? They are quite cute, these mice with their nevi... And they have a higher risk of melanoma skin cancer, just like us!

Abnormal scatter factor seems to develop in certain body cells accidentally, called spontaneous autosomal dominant genetic mutations. These mutations aren't hereditary. The only way 2 children in the same family could both develop a nevus is if each one independently mutates to develop abnormal scatter factor. Of course, that happens very, very rarely, once or twice in our whole group. On a rare occasion, a few relatives of a person with a nevus will also have a nevus. This is because both independently mutated to develop the abnormal scatter factor. We have about 5-6 families in our 1,000 families who have a relative with a nevus. At the moment, there is no known method of preventing abnormal scatter factor from occurring.  Many of our parents have wondered if something they did or did not do during the pregnancy could have caused their child to be born with a giant nevus, but we have not yet discovered any common finding. It appears to be just one of those things that happens by chance, as we have identical twins in the same environment in their mommy's belly, one with a giant nevus and one without! In the grand scheme of things, there are certainly many, many worse things that could happen to a person. Most of us are just thankful we are able to enjoy life as much as we can. We've learned to say, "This could have happened to anyone. Why not me?" instead of asking, "Why me?" In fact, a few of us feel that having a giant nevus has been a blessing in our lives. In many ways, we are luckier than normals. The giant nevus gives us the opportunity to have a better life here: do good, help others, be more empathetic, leave the earth a better place, be released from materialism and fear of aging, and many, many other benefits.

Congenital nevi usually form on the baby in the womb between 2nd and 6th month of pregnancy.  A nevus is often symmetrical around the spinal cord because the spinal cord and skin develop together from those same early neuroectodermal cells. Maybe one day we can figure out how to prevent abnormal "scatter factor" from developing... and so prevent nevi from occurring. In the meantime, those mice induced to have giant nevi just like us are so absolutely fascinating!


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