Neurofibromatosis Type I
Original Editors -Nick Pucillo & Cody Russell from Bellarmine University's Pathophysiology of Complex Patient Problems project.
Top Contributors - Nicholas Pucillo, Cody Russell, Lucinda hampton, WikiSysop, Elaine Lonnemann, Kim Jackson, Shaimaa Eldib and Wendy Walker
Definition/Description[edit | edit source]
Neurofibromatosis Type 1 (NF1) is an autosomal dominant disorder on the long arm of chromosome 17, characterized by benign tumor growth on nerve sheathes called neurofibromas and cutaneous spotting called café-au-lait macules. The role of the mutated, naturally occurring protein neurofibromin is not fully understood but does appear to play some role in regulating Ras proteins which promote cell division and growth. NF1 varies a great deal in presentation and complications, even between immediate family members.[1][2]
Prevalence[edit | edit source]
Neruofibromatosis type 1 affects approximately 1 in 3,000 peolple worldwide. Neruofibromatosis occurs equally between sexes and races.[3]
Characteristics/Clinical Presentation[edit | edit source]
Neurofibromatosis type 1 has dermal, ocular, neoplastic, neurologic, cardiovascular, and orthopaedic manifestations. These various manifestations are what calls for aggressive treatment from a multidisciplinary team.
Dermal Manifestations
- Cafe-au-lait macules (CALM): CALM is one of the most prevelant features of NF1. These macules are usually on of the first features to present in patients. These lesions are flat along the patient's skin and have a coffee-colored hyperpigmentation. The lesions are also round with well-defined borders and have an average diameter of 2-5 cm. [3] CALM is one of the cardinal diagnostic criteria for NF1. When multiple macules are present, NF1 is highly suggestive. [4]
- Skin Fold Freckling: Skin fold freckling are little brown macules that appear in regions where freckling is uncommon. These areas include the axilla, inguinal region, breask folds, neck, and upper eyelids. [3] Skin fold freckling is also involved in the diagnostic criteria for NF1 and usually occurs around the ages of 3 to 5 years. [4]
Ocular/Orbital Manifestations
- Lisch Nodules: Lisch nodules are hyperpigmentations of the iris. The hamartomas are affected consisting of a spindle-shaped cells. Lisch nodules do not cause visual impairments. [3] Visualization requires slit lamp examination by experienced practitioner. Eye examination is necessary in individuals in which the diagnosis of NF1 is uncertain. [4]
- Optic Pathway Glioma (OPGs): OPG is a tumor of the optic nerve and is present in 15% to 20% of NF1 patients. The tumor is slow growing and clinically presents as eye proptosis, decreased visual acuity, or percous puberty. Symptoms usually present before the age of 6 with diagnosis made by 3 years of age. [4]
Neoplastic Manifestaions
- Neuofibroma: Neuorfibromas are bening neoplasms of peripheral nerve sheaths. They are composed os schwann cells, fibroblast, perineural cells, and mast cells. Neurofibromas typically evolve in late childhood. Nerofibromas can increase in both size and magnitude with time with periods of accelerated proliferations during puberty and pregnancy. [3] Neuofibromas are a hallmark sign of NF1 and present as dome-shaped, soft, fleshy, slightly hyperpigmentated cutaneous tumors. Subcutaneous neruofibromas present as firm and nodular. [4]
- Plexiform Neurofibroma (PN): The plexiform neuorbifroma differs from cutaneus neruofibroma in that PN is usually congenital. PNs present as hyperpigmentated and/or hypertrichosis tumors and can develop into malignant peripheral nerve sheath tumors. [4]
- Malignancies: Individuals with NF1 are at a greater risk of developing bening and malignant neopalsms. These neoplasms include melanoma, leukemia, rhabdomyosarcoma, pheochromocytoma, carcinoma, and pancreatic endocrine tumors. [3]
Neurologic Manifestations
- Learning Disability: 75% of NF1 children have some sort of learning disability. Speech and language deficits have been noted along with delayed gross motor development. [3] Frequent assessments must be made for developmental mileston delays, learning disabilities, and school performances. [4]
Cardiovascular Manifestations
- Individuals with NF1 are at a greater risk for stroke, hypertension, congenital heart disease, and vasculopathy. [3]
Associated Co-morbidities[edit | edit source]
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Medications[edit | edit source]
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Diagnostic Tests/Lab Tests/Lab Values[edit | edit source]
Neruofibramatosis type 1 is diagnosed through through clinical assessment including patient history and physical examination. The National Institutes of Health have developed a diagnostic criteria for NF1 based upon common clinical features. The diagnosis is made by an individual having 2 or more of the following features:
- Six or more cafe au laite macules > 5 mm in prepubertal individuals and > 15 mm in diameter in adults.
- Two or more neruorfibromas.
- Freckling in the axillary or inguinal regions.
- Optic glioma visual pathways tumors most often presenting as grade I pilocytic astrocytomas.
- Two or more Lisch Nodules
- Abnormal development of the spine (scoliosis), the sphenoid bone, or the tibia.
- A first degree relative with NF1
Early diagnosis is challenging because of the variable characteristics of NF1.[1] Diagnosis my be delayed due to the different ages that features can emerge. [3]
Etiology/Causes[edit | edit source]
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Systemic Involvement[edit | edit source]
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Medical Management (current best evidence)[edit | edit source]
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Physical Therapy Management (current best evidence)[edit | edit source]
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Alternative/Holistic Management (current best evidence)[edit | edit source]
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Differential Diagnosis[edit | edit source]
Following is a comprehensive list of diagnosis that potential mimic NF1 :
Other forms of neurofibromatosis
• Segmental/mosaic NF1 (http://www.nfauk.org/assets/downloads/SEGMENTAL%20NF1%20June%202011-6.pdf)
• Watson syndrome (http://rarediseases.info.nih.gov/gard/5540/watson-syndrome/resources/1)
• Autosomal dominant multiple café au lait patches alone (some allelic with NF1) (http://escholarship.org/uc/item/3d56c2q8)
• Neurofibromatosis 2 (http://www.physio-pedia.com/Neurofibromatosis_Type_II)
• Schwannomatosis (http://www.ctf.org/Learn-About-NF/Schwannomatosis.html)
Other conditions with café au lait patches
• McCune–Albright syndrome (http://ghr.nlm.nih.gov/condition/mccune-albright-syndrome)
• DNA repair syndromes (http://www.geneskin.org/dna-repair-disorders.aspx)
• Homozygosity for one of the genes causing hereditary non‐polyposis cancer of the colon. (http://www.ncbi.nlm.nih.gov/books/NBK1211/)
Conditions with pigmented macules confused with NF1
• LEOPARD syndrome (http://ghr.nlm.nih.gov/condition/multiple-lentigines-syndrome)
• Neurocutaneous melanosis (http://www.ncbi.nlm.nih.gov/pubmed/1869648)
• Peutz–Jeghers syndrome (http://ghr.nlm.nih.gov/condition/peutz-jeghers-syndrome)
• Piebaldism (http://ghr.nlm.nih.gov/condition/piebaldism)
Localised overgrowth syndromes
• Klippel–Trenauny–Weber syndrome (http://ghr.nlm.nih.gov/condition/klippel-trenaunay-syndrome)
• Proteus syndrome (http://ghr.nlm.nih.gov/condition/proteus-syndrome)
Conditions causing tumours confused with neurofibromas
• Lipomatosis (http://www.pathologyoutlines.com/topic/softtissueadiposelipomatosis.html)
• Banayan–Riley–Ruvalcuba syndrome (http://ghr.nlm.nih.gov/condition/bannayan-riley-ruvalcaba-syndrome)
• Fibromatoses (http://rarediseases.info.nih.gov/gard/6439/fibromatosis/resources/1)
• Multiple endocrine neoplasia type 2B (http://ghr.nlm.nih.gov/condition/multiple-endocrine-neoplasia)
Case Reports/ Case Studies[edit | edit source]
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Resources
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Recent Related Research (from Pubmed)[edit | edit source]
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References[edit | edit source]
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- ↑ 1.0 1.1 Julian N, Edwards NE, DeCrane S, Hingtgen CM. Neurofibromatosis 1: Diagnosis and Management. The Journal for Nurse Practitioners. 2014;10(1):30-35.
- ↑ Genetics Home Reference. Neurofibromatosis type 1. Available at: http://ghr.nlm.nih.gov/condition/neurofibromatosis-type-1. Accessed March 4, 2014].
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 3.8 Feldman DS, Jordan C, Fonseca L. Orthopaedic manifestations of neurofibromatosis type 1. J Am Acad Orthop Surg. 2010;18(6):346-57.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 Boyd KP, Korf BR, Theos A. Neurofibromatosis type 1. J Am Acad Dermatol. 2009;61(1):1-14.
