Diagnostic Criteria

It’s important to know that an accurate diagnosis of NF1 can only be made by a physician with expertise in the diagnosis and treatment of neurofibromatosis. Because people with NF1 often have multiple café-au-lait spots, the disorder should be suspected in someone with six or more spots, at least five millimeters in size before puberty and 15 millimeters in size after puberty. There is no relationship between the number of café-au-lait spots and the severity or prognosis of the disorder.

While the presence of café-au-lait spots is one criterion for the diagnosis, at least two features of the disorder need to be present to confirm the condition. A diagnosis of NF1 is made through an extensive physical examination and, in some cases, biopsies, imaging studies, or additional medical tests to confirm the presence of any of the following diagnostic criteria of NF1 established by the National Institutes of Health (NIH) in 1987 based on a consensus of experts in the field.

Observational Approach

Because many features of NF1 are age-related, they are not often present in very young children with the disorder. Many features often appear over time – frequently not until late childhood (age 7-10) or adolescence and the onset of puberty.

As a result, it is often impossible to make a definitive diagnosis of NF1 in a young child with only multiple café-au-lait spots. Also, there are other conditions, for example a rare disorder called Legius syndrome, that can be associated with multiple cafe-au-lait spots. Legius syndrome is not associated with the tumors that occur in NF1; it is often necessary to do genetic testing to distinguish Legius syndrome from NF1 in a young child who presents only with cafe-au-lait spots.

Even if the child is affected, it could take years before another feature of the disorder appears to confirm the diagnosis. For this reason, doctors often annually reexamine these children to look for the appearance of new features. If any are found, the diagnosis is clear; if not, the question remains unsettled.

In cases where a diagnosis cannot be made based on the presence of physical symptoms, genetic testing for the NF1 gene mutation is currently available and may be appropriate for some families in order to confirm a diagnosis of NF1. A genetic counselor can provide guidance and information regarding the suitability of genetic testing in these cases.

For more information, please contact the UAB Neurofibromatosis Program at 205-934-4983.