Learning disabilities; overt mental retardation is uncommon.
Malignant risk Patients with NF-1 have an estimated 3% to 15% lifetime risk of malignant disease- The two most common types of malignant tumors arc neurofibrosarcoma and optic nerve gliomas Other malignancies associated with NF-1 include.
Malignant myeloid disorders,
Neurofibromatosis type 2 (NF-2) NF-2, also known as central neurofibromatosis, accounts for about 3% of cases of NF and results from defects in the NF-2 gene on chromosome 27. Much less common than NF-1,
Etiology and pathogenesis The gene for NF-2 is located on chromosome 22 at 22qll . In patients with NF-2, loss of heterozygosity for this region of chromosome 22 has been demonstrated in acoustic neuromas, neurofibromas, and mcningiomas.
Clinical features and presentation The diagnostic criteria for NF-2 are either
bilateral eighth nerve masses confirmed by CT or MRI or
a first-degree relative with NF-2 and either a unilateral eighth nerve mass or two of the following: neurofibroma, meningioma, glioma, schwannoma, or juvenile posterior subcapsular lenticular opacity
Skin manifestations in NF-2 are less prominent than in NF-I. CAL tend to be fewer in number and show less distinct hyperpigmentation.
Intertriginous freckling is not present.
Neurofibromas, especially the plexiform variant, are the least common cutaneous finding in NF-2
One characteristic skin finding includes cutaneous and subcutaneous schwannomas, the most common of the various tumors seen in NF-2. Schwannomas typically present as superficial, discrete, slightly raised papules in which the surface is rough, often pigmerited, and covered by excess hair
Tuberous sclerosis complex Tuberous sclerosis complex (TSC) is the second most common neurocutaneous disorder. The transmission is autosomat dominant; The classic triad of adenoma sebaccum,seizures, and mental retardation (epiloia).
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