Neurofibromatosis type 1 (NF1) is a relatively common genetic disease that affects approximately one out of every 3,000 people. This genetic disease can lead to various ophthalmic conditions, tumor growth, memory deprivation, learning deficits, and several other life-threatening and uncomfortable symptoms. Genetic testing is available to confirm a diagnosis of NF1, however, differential diagnosis still requires a clinical methodology. In 1988, the National Institute of Health (NIH) synthesized a criterion of seven symptoms of NF1, of which the patient must meet two, to accurately diagnose NF1 patients. These criteria are outdated and have led to the misdiagnoses of several patients, especially in children below the age of eight, because they often are late to display common symptoms. A late diagnosis can lead to unnecessary treatments, misdiagnosis, and, if the diagnosis is severely delayed, life-threatening conditions. Children below the age of eight often display other symptoms correlated with NF1 that were omitted from the criteria, such as hemifacial hypertrophy. In order to validate hemifacial hypertrophy as a criterion for NF1 patients, I plan to conduct a study that will examine cases of delayed diagnosis of NF1, due to the late presentation of NIH validated symptoms. I will then analyze the percentage of these patients who had hemifacial hypertrophy prior to the age of eight and create a list of patient cases of those diagnosed with NF1 after the age of eight. Then I will record the amount of patients that presented hemifacial hypertrophy prior to their diagnosis and statistically analyze these results.