Type 1 Neurofibromatosis Sans Neurofibroma: A Case Report Emphasizing the Role of Ocular Examination

Abstract

Neurofibromatosis type 1 (NF1) is one of the most common genetic disorders and is inherited in an autosomal dominant fashion. NF1 is a member of the RASopathies, a class of congenital disorders brought on by mutations in the Ras/mitogen-activated protein kinase pathway. Dermatologic manifestations are typically prevalent in NF1 individuals. Multiple café-au-lait macules (CALMs) may be present at birth or develop in the 1st year of life. Other cutaneous manifestations like freckles in the skinfolds appear in early childhood. Neurofibromas are present in almost all adult patients and may be cutaneous, subcutaneous, or along the peripheral nerves, but their appearance may be delayed till adulthood. CALMs and skinfold freckling are not specific for NF1, and we may need to consider other differential diagnoses like Legius syndrome. A recent modification of the diagnostic criteria includes the identification of the genetic abnormality to facilitate diagnosis in children who may not have cutaneous neurofibromas. This emphasizes the added value of genetic analysis in a condition which is generally a clinical diagnosis. Lisch nodules generally occur by about 7 years of age and are present in 90% of cases. Their presence can help differentiate from Legius syndrome with its more benign course without genetic analysis. We report the case of a 14-year-old male with NF1 who had no cutaneous neurofibromas to reiterate the importance of ophthalmic evaluation in all cases of NF1, especially in resource-poor settings where genetic studies may not be possible.

Keywords

• café-au-lait macules
• neurofibroma
• ocular examination