Loading presentation...

Present Remotely

Send the link below via email or IM

Copy

Present to your audience

Start remote presentation

  • Invited audience members will follow you as you navigate and present
  • People invited to a presentation do not need a Prezi account
  • This link expires 10 minutes after you close the presentation
  • A maximum of 30 users can follow your presentation
  • Learn more about this feature in our knowledge base article

Do you really want to delete this prezi?

Neither you, nor the coeditors you shared it with will be able to recover it again.

DeleteCancel

Make your likes visible on Facebook?

Connect your Facebook account to Prezi and let your likes appear on your timeline.
You can change this under Settings & Account at any time.

No, thanks

Neurofibromatosis

AP Biology: Cell Signalling Project
by

Autumn Rafuse

on 8 January 2013

Comments (0)

Please log in to add your comment.

Report abuse

Transcript of Neurofibromatosis

Neurofibromatosis Type 1 Neurofibromatosis type 1, or NF1, is a genetic disorder which results in the growth of noncancerous tumors called neurofibromas (Learn genetics, 2012). These neurofibromas generally form on or just below the skin, in the brain, or in other areas of the peripheral nervous system; neurofibromas may however also be found in other areas of the body such as the eye (Learn genetics, 2012). Neurofibromatosis type 1 is caused by a mutation of the NF1 gene located on chromosome 17 (Learn genetics, 2012). In 50% of neurofibromatosis type1 cases the mutation of the NF1 gene is inherited from a parent, neurofibromatosis type 1 is inherited in an autosomal dominant pattern, this means that inheriting only one copy of the mutated gene will cause neurofibromatosis (Learn genetics, 2012). The remaining 50% of NF1 cases are caused by non-hereditary mutations. The NF1 gene is very susceptible to mutations due to it's large size (Learn genetics, 2012). What is It? DNA is translated to RNA, mRNA is transcripted to a polypeptide. The polypeptide folds to make the neurofibromin protein. Neurons Schwann cells Neurofibromin is produced in: Neurofibromin Muscle cells What's Happening? What Does it Do? The NF1 gene is very large gene, which is responsible for the production of the neurofibromin protein (Learn genetics, 2012). Neurofibromin is found in many different cells, including neurons, Schwann cells, and muscle cells (Genetics home reference, 2007). Neurofibromin acts as a tumor suppressor protein, a protein that stops a cell from growing and dividing too quickly, or in an uncontrolled manner (Genetics home reference, 2007). Neurofibromin does this by regulating the ras protein (Learn genetics, 2012). What Is Ras? The ras protein is a G protein, which acts as a messenger by relaying a signal from a growth factor receptor located on the plasma membrane to a phosphorylation cascade consisting of protein kinases (Campbell & Reece, 2005). When a growth factor binds to the receptor on the plasma membrane of a cell its signal is passed to an active, GTP bound, ras protein, which in turn triggers a phosphorylation cascade (Campbell & Reece, 2005). This cascade causes the cell to respond by synthesizing a protein that promotes cell division (Campbell & Reece, 2005). How Does it Work? Neurofibromin, the protein encoded by the NF1 gene, regulates the ras protein by acting as an inhibitor. Neurofibromin serves to inactivate the ras protein by causing it to bind a GDP making it inactive, opposed to binding a GTP making it active. In a healthy cell neurofibromin will, when needed, inhibit the ras protein causing the cell to stop growing and dividing. In the cell of an individual affected by neurofibromatosis type 1, a mutation to the NF1 gene causes a shortened version of the neurofibromin protein to be synthesized, this shortened version cannot perform its function of inhibiting the ras protein, and the cell will divide uncontrollably (Genetics home reference, 2007). This uncontrolled division results in the formation of neurofibromas, benign tumors associated with Neurofibromatosis type 1(Genetics home reference, 2007). Neurofibromin, the protein encoded by the NF1 gene, regulates the ras protein by acting to deactivate it. Neurofibromin serves to inactivate the ras protein by causing it to bind a GDP making it inactive, opposed to binding a GTP making it active. Ras Ras Ras Ras NF1 GTP GDP Genetic Science Learning Center (2012, August 6)
Neurofibromatosis Type 1.Learn.Genetics. Retrieved December 18, 2012, from http://learn.genetics.utah.edu/content/disorders/whataregd/nf1/

Genetics home reference. (2007, March). Retrieved from
http://ghr.nlm.nih.gov/gene/NF1

Cambell, N., & Reece, J. (2005). Biology. (7th ed., pp. 371-373). San Francisco: Benjamin
Cummings.

Bethesda. (2012). Retrieved from National Institutes of Health website:
http://www.ninds.nih.gov/disorders/neurofibromatosis/neurofibromatosis.htm

Carcavilla, A. (2011). LEOPARD syndrome (PTPN11, T468M) in three boys fulfilling
neurofibromatosis type 1 clinical criteria. European Journal Of Pediatrics, 170(8), 1069. doi:10.1007/s00431-011-1418-5

Sehgal, V. (2009). Evaluation of plexiform neurofibroma in neurofibromatosis type 1 in 18
family members of 3 generations: ultrasonography and magnetic resonance imaging a diagnostic supplement. International Journal Of Dermatology, 48(3), 275. doi:10.1111/j.1365-4632.2009.03999.x

(2006). Cancer genomics. Retrieved from
http://www.cancer.gov/cancertopics/understandingcancer/cancergenomics/page49

Englert, C. (2010, Sept 09). Medlineplus. Retrieved from
http://www.nlm.nih.gov/medlineplus/ency/article/000847.htm

Pediatric Orthopaedic Society of North America. (2007, 08). Neurofibromatosis. Retrieved
from http://orthoinfo.aaos.org/topic.cfm?topic=A00050

Cömert, E. (2012). Outcomes in 12 gynecologic cancer patients with brain metastasis: a
single center's experience. Turkish Journal Of Medical Sciences, 42(3), 385. doi:10.3906/sag-1101-1382

Ploumis A. Radiculopathy in Degenerative Lumbar Scoliosis: Correlation of Stenosis with
Relief from Selective Nerve Root Steroid Injections. Pain Medicine [serial online]. January 2011;12(1):45. Available from: Advanced Placement Source, Ipswich, MA. Accessed December 19, 2012. The Big Picture In a healthy cell neurofibromin will, when needed, inactivate the ras protein causing the cell to stop growing and dividing (Genetics home reference, 2007). In the cell of an individual affected by neurofibromatosis type 1, a mutation to the NF1 gene causes a shortened version of the neurofibromin protein to be synthesized, this shortened version cannot perform its function of inactivating the ras protein, and the cell will divide uncontrollably (Genetics home reference, 2007). This uncontrolled division results in the formation of neurofibromas, benign tumors associated with Neurofibromatosis type 1(Genetics home reference, 2007). As cell divide uncontrollably they begin to form neurofibromas, benign tumors, found throughout the body. Neurofibromatosis type 1 is characterized by the formation of neurofibromas along nerves in the brain, specifically the optic nerve, near the spinal cord, and on nerves on or just below the surface of the skin (Bethesda, 2012). A patient can have any number of neurofibromas throughout their body, from three or four to thousands (Learn genetics, 2012). Additional symptoms of neurofibromatosis type 1include high blood pressure, short height, an abnormally large head, and skeletal irregularities such as scoliosis. Those with neurofibromatosis type 1 also have a high incidence of learning disabilities such as ADHD (Genetics home reference, 2007). Symptoms vary greatly from patient to patient for reasons unknown to scientists and medical professionals, there is however speculation that an individual’s unique genetic make-up will influence the severity of their symptoms (Learn genetics, 2012). In rare cases the benign neurofibromas may become cancerous; this means that those with neurofibromatosis type one have an increased risk of cancer, specifically brain tumors and leukemia (Genetics home reference, 2007). There is no treatment for neurofibromatosis, there are surgical options to remove tumors and correct bone damage, there is however no cure for the disorder itself (Learn genetics, 2012). Since the discovery of the location and function of the NF1 gene research surrounding neurofibromatosis has really changed (Bethesda, 2012). The discovery of this gene has promoted researchers to search for other genes which may influence the growth or suppression of neurofibromatosis-related tumors (Bethesda, 2012). There is also research being conducted to determine why the mutations of the NF1 gene that cause neurofibromatosis type 1 also cause the abnormal development and formation of nerve cells and nerve networks in fetuses, which later cause learning disabilities (Bethesda, 2012). References Neurofibromatosis is also characterized by café-au-lait spots, flat patches of darkly pigmented skin, and Lisch nodules, benign growths in the iris of the eye (Genetics home reference, 2007). What's Next?
Full transcript