NF1 and neurofibromatosis type 1: Choroidal abnormalities were added as an ophthalmologic criterion because of the high specificity and sensitivity for NF119,29 and for the ability to differentiate NF1 from LGSS.19 In the revised diagnostic criteria, either Lisch nodules or choroidal abnormalities is sufficient for this criterion; choroidal abnormalities were not included as a separate criterion since isolated ophthalmologic findings, even if bilateral (e.g., an individual with only two Lisch nodules and two choroidal abnormalities) are likely to reflect mosaic NF1 rather than constitutional NF1.