Neurofibromatosis type 1 in children

To document ophthalmic and general characteristics of Neurofibromatosis Type 1 (NF1) in children; and to characterize the iris changes of NF1 including their variability and reliability.

One hundred and ninety-six patients with NF1 were evaluated for general characteristics; 156 patients underwent prospective eye evaluations; and 151 NF1 patients and controls had iris photography in accordance with a protocol. Masked evaluation of photographs compared to a known diagnosis, and interobserver reliability tests were performed.

Incidence of iris changes consistent with NF1 (Lisch nodules, plus) by age group; spectrum of iris changes found; correlation of iris findings to known diagnosis and Kappa coefficients for interobserver reliability.

Iris changes were common in children over age 5, and increased with age; masked evaluation of photographs compared to a known diagnosis yielded fair to poor correlation (Kappa = -.02 to .50); interobserver reliability was poor (Kappa = -.02 to .24, overall .174); iris changes found in NF1 are more diverse than classic descriptions of Lisch nodules, and including a broader spectrum probably increases the sensitivity and decreases the specificity of their diagnostic value.

Iris changes as a diagnostic marker for NF1 may need rethinking; this study calls to question their reliability and validity.