Neurofibromatosis: Neurofibromatosis (NF) is an autosomal dominant disorder with numerous presentations affecting nearly every organ system. The 2 major subtypes are NF type 1 (NF1), also known as peripheral NF, and NF type 2 (NF2), referred to as central NF. However, these terms are not completely correct because NF1 may cause central characteristics.

About 50% of cases of NF are familial, and the other 50% are due to spontaneous gene mutation. NF1, also known as von Recklinghausen disease, is a common genetic disorder involving a gene mutation on chromosome 17 that affects 1 in every 3000-4000 births (Children's Tumor Foundation, 2006). This disorder affects all races and both sexes equally (Neurofibromatosis, Inc, 2006). The diagnosis of NF1 requires that the patient present with 2 or more of the following conditions: 6 or more café au lait spots (irregularly shaped, evenly pigmented, brown macules), 2 or more neurofibromas, axillary or inguinal freckling, Lisch nodules on the iris, optic glioma, various types of osseous lesions, or a first-degree relative with the condition.

Symptomatic NF1 typically manifests as flesh-colored, benign skin tumors that appear late in childhood. The patient may have as few as 3 or as many as thousands of these benign lesions, which consist of Schwann cells, neural fibroblasts, mast cells, and vascular elements. Neurofibromas may occur anywhere in the body and potentially lead to marked disfigurement. Lesions along visual, auditory, or CNS nerve pathways may result in blindness, deafness, or neurologic deficits. Other findings associated with this condition include skeletal anomalies, such as fibrous dysplasia, subperiosteal bone cysts, or vertebral scalloping (Neurofibromatosis, Inc, 2006).

NF2 is a progressive genetic disorder affecting 1 in every 33,000-40,000 births (Neurofibromatosis, Inc, 2006). Patients with NF2, which results from an abnormality of chromosome 22, typically present with acoustic neuromas or vestibular schwannomas. Clinical manifestations include tinnitus, balance disorders, and progressive hearing loss. Affected patients may also have meningiomas and juvenile cataracts. The diagnosis is based on a history of the condition in a first-degree relative and on any 2 of the conditions listed above for NF1 (Neurofibromatosis, Inc, 2006).

For both NF1 and NF2, the diagnosis is primarily based on physical findings and a positive family history. Diagnostic tests that may be useful include radiographic studies, such as CT of the brain, genetic analysis, and psychological or developmental assessment.

No cure exists for this condition. Recommendations for follow-up include referral to support groups, psychological counseling, evaluation of learning disorders, surgical excision of lesions, and regular monitoring by a primary care provider for any changes that may occur, as patients with NF1 are at somewhat increased risk of malignancy. Annual ocular examinations are recommended. Genetic testing is also advocated in patients with NF who wish to have children. Surgery has been a successful treatment for the lesions themselves; however, recurrence often occurs, and nerve damage is a risk when tumors are located along neural pathways (National Institute of Neurologic Disorders and Stroke, 2006).


References

• Children's Tumor Foundation: Diagnosis of NF1. Available at: http://www.ctf.org/aboutnf/nf1/diagnosisnf1.htm. Accessed July 29, 2006.
• Children's Tumor Foundation: Diagnosis of NF2. Available at: http://www.ctf.org/aboutnf/nf2/diagnosisnf2.htm. Accessed July 29, 2006.
• Neurofibromatosis, Inc: What is NF? Available at: http://www.nfinc.org/what.shtml. Accessed July 29, 2006.
• NINDS: National Institute of Neurologic Disorders and Stroke. Neurofibromatosis Fact Sheet. Available at: http://www.ninds.nih.gov/disorders/neurofibromatosis/
  detail_neurofibromatosis.htm#57453162. Accessed July 29, 2006.