[Neurofibromatosis--an inborn genetic disorder with susceptibility to neoplasia]

Among different subtypes of neurofibromatosis (Nf), type 1 (Nf-1) predominates in frequency (approximately 97% of Nfs' patients) with an incidence of approximately 1 in 3500 live births. Nf-2, comprises 2% of the Nf population and is a very rare disease (1:40,000). Both are autosomal dominant disorders with 100% penetration, variable expression and 50% rate of new (de novo) mutations. The protein products of both, NF1 andNF2 genes are best known and the genes serve as tumour suppressors. Mutations result in a predisposition to develop a variety of tumours of the central and peripheral nervous systems, as well as other malignancies. Nf-2 is a multisystem genetic disorder associated with bilateral vestibular schwannomas, spinal cord schwannomas, meningiomas, gliomas, and juvenile cataracts with a paucity of cutaneous features, which are seen more consistently in Nf-1. In contrast to Nf-1, Nf-2 is associated with significant morbidity and decreased life span and a higher incidence of CNS tumours. However, morbidity and mortality rates in Nf-1 are not negligible. The cardinal features of Nf-1 are cafe-au-lait spots, axillary and inguinal freckling, cutaneous neurofibromas, and iris hamartomas (Lisch nodules). Optic gliomas and both malignant and benign peripheral nerve sheet tumours are the most common malignancies arising in Nf-1 patients. Among neurological symptoms epilepsy, intellectual disability and learning difficulty are also observed. Bone dysplasia results in scoliosis. There is no known medical treatment beneficial to both groups of patients. The mainstay of care for Nf patients is anticipatory guidance, and early detection and symptomatic treatment of disease complications.