Neurofibromatosis (a.k.a. von Recklinghausen disease) is a genetic disorder of the nervous system that causes benign tumors to form on the nerves anywhere in the body at any time. At least eight varieties of NF exist and can range from very mild to quite severe, but none is as disfiguring as the tragic case of the Elephant Man (who we now know did not have NF).

Café-au-lait spots are a classic feature of this disease. These flat birthmarks with distinct edges are a bit darker than the surrounding skin. In light-skinned individuals, they are the color of coffee with lots of cream. In those with darker skin, they can be the color of a rich, full-bodied, black coffee. The spots can increase in size, number, and darkness throughout childhood.

Neurofibromatosis is diagnosed not with a test but by the presence of certain physical findings. People can receive a firm diagnosis of NF if they have any two of the following symptoms (Textbook of Pediatrics, WB Saunders, 2004):

• At least five café-au-lait spots more than 5 mm in the greatest diameter (before puberty) or at least six café-au-lait spots of more than 15 mm (after puberty).
• Underarm or groin freckling.
• Two or more Lisch nodules (small nodules in the iris of the eye).
• Two or more neurofibromas (rubbery lumps under the skin, often slightly purplish over the lump--these usually don't show up before puberty).
• A bone lesion consistent with NF, such as scoliosis, frequent fractures, or a hunchback.
• Optic gliomas (small benign tumors of the optic nerve--most still have normal or near-normal vision).
• A close relative with NF (parent, sibling, or child).

Many of these findings do not show up in early childhood. Thus, any child with five or more café-au-lait spots that are more than 5 mm in diameter should be monitored and treated as having NF. This means a baseline examination by an ophthalmologist and audiologist (including vision and hearing tests). It also means a baseline EEG and head CT or MRI, as well as a skeletal survey radiograph and a visit with a geneticist.