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Neurofibromatosis (NF) type I (NF-I), also called von
Recklinghausen disease, is a rare genetic disorder characterized by the
development of multiple neurofibromas of the nerves and skin.
The presence of café-au-lait spots on the skin of the trunk and other regions, as well
as freckling, particularly in the axillary region and in the inguinal area is
characteristic of this medical condition.
Often evident by age 1 year, the café-au-lait spots tend to increase in size and number over
time. At birth or early childhood, plexiform neurofibromas may be present.
Benign tumor-like nodules of the colored regions of the eyes (Lisch nodules)
may be present. Other features include macrocephaly, seizures, scoliosis,
and bowing of the lower legs.
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Type I: Neurofibromatosis von Recklinghausen; Fibromatosis
Molluscum Multiplex; Elephantiasis Neuromatoses.
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Neurofibromatosis is more a spectrum of disorders
classified as follows:
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- NF-I, or peripheral NF, is best known as von Recklinghausen neurofibromatosis (VRNF).
- NF-II, or central NF, is bilateral acoustic neuroma NF (BANF).
- NF-III appears to combine at least some features of types I and II.
- NF-IV also represents a heterogeneous category (Lisch nodules in the iris are
absent).
- NF-V, or segmental NF, is restricted in its involvement of the body.
- NF-VI manifests primarily as café-au-lait spots without neurofibromas.
- NF-VII is a late-onset variety.
- NF-NOS represents forms of NF that do not appear to fit into categories I to
VII.
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In a review article published in JAMA in 1997, Gutmann et al. seem to categorize
forms other than NF-I and NF-II as mosaic NF. These individuals may require more
detailed counseling than patients with the usual presentation.
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Approximately 1:3000 in the general population. One
million patients estimated in 1987 worldwide. NF-I = 1:4000, NF-II =
1:50,000 in the general population.
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Usually autosomal dominant but heterogenic
(half of probands represent new mutations). The NF-I defect is on chromosome
17q11.2, and NF-II is caused by a change in the long arm of chromosome 22.
NF-I gene produces neurofibromin, which is considered a tumor suppressor
gene controlling ...