Type I neurofibromatosis — clinical features and diagnosis

Abstract

Disorders in the embryonic development affecting three germ layers result in the formation of skin-muscular syndromes — phakomatoses. Type 1 neurofibromatosis (NF-1) is the most common phakomatosis. NF-1, also known as Recklinghausen’s disease, occurs at a frequency of 1:2500–1:3000, with equal distribution in males and females regardless of race, and is caused by mutations of the NF1 gene on the long arm of chromosome 17q11.2. This is an autosomal dominant disease with variable gene expression and incomplete penetration, resulting in variable clinical picture. Over 70% of patients are diagnosed between 5th and 18th year of age. Café-au-lait spots, neurofibromas, plexiform neurofibromas, skinfold freckling, optic nerve glioma, Lisch nodules and skeletal abnormalities are the most common symptoms. Café-au-lait spots occur in 99% of patients, but neurofibromas, which are tumors of the peripheral nerve sheaths, are the hallmark of this disease.