Rhiannon Raventhorn's blog: "Raven Haven"

created on 03/23/2012 | http://fubar.com/raven-haven/b347218 | 3 followers

posted on 03/10/2013&nbs-07:00;@&nbs-07:00;08:03&nbs-07:00;pm

What is neurofibromatosis type 1?
http://fubar.com/what-is-neurofibromatosis-type-1/b347218-1194291

What is neurofibromatosis type 1? (Back to Top)
Neurofibromatosis type 1 (NF1) is an inherited condition characterized by changes in skin coloring (pigmentation) and the growth of tumors along nerves in the skin, brain, and other parts of the body. The signs and symptoms of this condition vary widely among affected people. Mutations in the NF1 gene cause neurofibromatosis type 1. This condition is considered to have an autosomal dominant pattern of inheritance.^[1]
Last Reviewed: 11/9/2011
What are the signs and symptoms of neurofibromatosis type 1 (NF1)? (Back to Top)
Beginning in early childhood, almost all people with NF1 have multiple café-au-lait spots, which are flat patches on the skin that are darker than the surrounding area. These spots increase in size and number as the individual grows older. Freckles in the underarms and groin typically develop later in childhood.^[1]

The eyes can also be affected by NF1. During childhood, benign growths called Lisch nodules often appear in the colored part of the eye (iris). Lisch nodules do not interfere with vision. Some affected individuals also develop tumors that grow along the nerve leading from the eye to the brain (the optic nerve). These tumors, which are called optic gliomas, may lead to reduced vision or total vision loss. In some cases, optic gliomas have no effect on vision.^[1]

Most adults with NF1 develop neurofibromas, which are noncancerous (benign) tumors that are usually located on or just under the skin. These tumors may also occur in nerves near the spinal cord or along nerves elsewhere in the body. Some people with NF1 develop cancerous tumors that grow along nerves. These tumors, which usually develop in adolescence or adulthood, are called malignant peripheral nerve sheath tumors. People with NF1 also have an increased risk of developing other cancers, including brain tumors and cancer of blood-forming tissue (leukemia).^[1]

Additional signs and symptoms of NF1 include high blood pressure (hypertension), short stature, an unusually large head (macrocephaly), and skeletal abnormalities such as an abnormal curvature of the spine (scoliosis). Although most people with NF1 have normal intelligence, learning disabilities and attention deficit hyperactivity disorder (ADHD) occur frequently in affected individuals.^[1]
Last Reviewed: 6/6/2012
What causes neurofibromatosis type 1 (NF1)? (Back to Top)
Mutations in the NF1 gene cause neurofibromatosis type 1. The NF1 gene is located on the long (q) arm of chromosome 17 at position 11.2.^[2]

The NF1 gene provides instructions for making a protein called neurofibromin. This protein is produced in many cells, including nerve cells and specialized cells surrounding nerves (oligodendrocytes and Schwann cells). Neurofibromin acts as a tumor suppressor, which means that it keeps cells from growing and dividing too rapidly or in an uncontrolled way. Mutations in the NF1 gene lead to the production of a non-functional version of neurofibromin that cannot regulate cell growth and division. As a result, tumors such as neurofibromas can form along nerves throughout the body. It is unclear how mutations in the NF1 gene lead to the other features of neurofibromatosis type 1, such as café-au-lait spots and learning disabilities.^[1]
Last Reviewed: 11/9/2011
How is neurofibromatosis type 1 (NF1) inherited? (Back to Top)
Neurofibromatosis type 1 is considered to have an autosomal dominant pattern of inheritance.^[1] People with this condition are born with one mutation in the NF1 gene in each cell of the body. In about half of cases, the altered gene is inherited from an affected parent. The remaining cases result from new mutations in the NF1 gene and occur in people with no history of the disorder in their family.^[1]

Unlike most other autosomal dominant conditions, in which one altered copy of a gene in each cell is sufficient to cause the disorder, two copies of the NF1 gene must be altered to trigger tumor formation in neurofibromatosis type 1.^[1] A mutation in the second copy of the NF1 gene occurs during a person's lifetime in specialized cells surrounding nerves. Almost everyone who is born with one NF1 mutation acquires a second mutation in many cells and develops the tumors characteristic of neurofibromatosis type 1.^[1]
Last Reviewed: 11/9/2011
How is neurofibromatosis type 1 diagnosed? (Back to Top)
The diagnosis of NF1 is usually made after a clinical exam and does not require laboratory tests.^[4] To make a diagnosis, a doctor looks for two or more of the following features:^[3]
- - Six or more light brown spots on the skin (“cafe-au-lait” spots), measuring more than 5 millimeters across in children, or more than 15 millimeters across in adolescents and adults
  - Two or more neurofibromas, or one plexiform neurofibroma (a neurofibroma that involves many nerves)
  - Freckling in the area of the armpit or the groin
  - Two or more growths on the iris of the eye (known as Lisch nodules or iris hamartomas)
  - A tumor on the optic nerve (optic glioma)
  - Abnormal development of the spine (scoliosis), the temple (sphenoid) bone of the skull, or the tibia (one of the long bones of the shin)
  - A parent, sibling, or child has been diagnosed with NF1
Symptoms such as café-au-lait spots, neurofibromas, Lisch nodules, and freckling are often seen at birth or shortly afterwards, and almost always by the time a child is 10 years old. Because many features do not develop until a person is older, it can take several years to make a diagnosis.^[3]
Last Reviewed: 6/6/2012
How might neurofibromatosis type 1 (NF1) be treated? (Back to Top)
There is currently no way to prevent or stop the growth of neurofibromas associated with NF1. Those that are disfiguring or irritating may be surgically removed. Treatment for malignant neurofibromas (occurring in 3 to 5 percent of cases) may also include radiation therapy or chemotherapy.^[3]^[4] Optic gliomas that threaten vision may be reduced in size by surgery or chemotherapy in some cases. Surgery can also correct some of the bone malformations (such as scoliosis) associated with NF1.^[3]^[4]
Last Reviewed: 6/6/2012

References (Back)

Neurofibromatosis type 1 . Genetic Home Reference Website. March 2007 Available at: http://ghr.nlm.nih.gov/condition=neurofibromatosistype1. Accessed March 18, 2011.
NF1 gene. Genetics Home Reference Website . 2007 Available at: http://ghr.nlm.nih.gov/gene/NF1. Accessed November 9, 2011.
Neurofibromatosis Fact Sheet. National Institute of Neurological Disorders and Stroke Website. August 2011 Available at: http://www.ninds.nih.gov/disorders/neurofibromatosis/detail_neurofibromatosis.htm. Accessed May 25, 2012.
Friedman JM. Neurofibromatosis 1. GeneReviews. 2012 Available at: http://www.ncbi.nlm.nih.gov/books/NBK1109/. Accessed May 25, 2012.