Nature of the Genetic Difficulty

Neurofibromatosis Type One (NF1) *The "spelling mistake" in the gene is found on chromosome 17 *The most common form of Neurofibromatosis, accounting for up to 90% of the cases *NF 1 has a disorder frequency of 1 in 4,000, making it more common than neurofibromatosis type 2
Neurofibromatosis Type Two (NF2) *The result of mutation of the merlin (also known as schwannomin) on chromosome 22 *It accounts for only 10% of all cases of NF, and its frequency is lower than NF1 Holds a frequency of 1 in 45,000 people
Schwannomatosis *Schwannomatosis is a genetic condition, but unlike NF1 and NF2 it does not have a clear pattern of inheritance. *Schwannomatosis often skips generations so that more distant family members with unexplained neurological symptoms *In 2007 a candidate gene for Schwannomatosis, called INI1, was identified. *There is as yet no definitive "Schwannomatosis genetic test" *Genetic testing for mutations in INI1 is available, though as the role of INI1 and the potential involvement of other genes in Schwannomatosis is still being defined *Schwannomatosis likely occurs in about 1 in 40,000 people, similar to NF2 *Commonly occurs with individuals that have NF2 and schwannomatosis

Basic Facts of Disease

*NF is one of the most common neurological conditions caused by a single gene mutation *NF occurs in all ethnic backgrounds, in both sexes, throughout the world *50% of new diagnoses occur without any other member of the family having NF o Otherwise known as a spontaneous gene mutation. *This means that potentially any baby is at risk of developing NF. *A parent who has NF has a 50% risk of passing NF on to their child *People affected by this condition develop non-cancerous tumors along their nerves. *The tumors are called neurofibromas. They are a mass of different types of cells that grow on and surround nerves. Neurofib.jpg
Facts about NF1 *NF1 is a common genetic condition *The early signs of NF1 are café au lait spots (flat brown birthmarks) on the skin, freckles in unusual places, and neurofibromas (lumps and bumps) on the skin. *One third of people will have one or more medical complication during their lifetime. *Mild learning difficulties are common in NF1
Symptoms of NF1· Noncancerous tumors under the skin or within body· Brown patches in the iris· Bowed legs, short stature, or bone abnormalities including scoliosis· Freckles in the groin or underarm area· Growth of a tumor on the optic nerve· Light brown skin tags· May cause learning disabilities, speech problems, and delays in an individual development.· Seizures, eye tumors, and high blood pressure may also affect people with this condition.· Rarely, the tumors may become malignant· In some cases, tumors may also affect organs within the body.
Facts about NF2 *NF2 is rare genetic condition *NF2 is usually diagnosed by MRI scans *In NF2 people develop nervous system tumours (lumps) typically in the brain and spine *NF2 can cause hearing loss, deafness, and mobility problems
Symptoms of NF2· People with condition develop tumors on the nerve that connects the ear to the brain- called schwannomas· Tumors on this nerve may cause hearing difficulties· Other complications may include dizziness, ringing in the ears, and balance issues· The pressure of the tumors on other nerves may cause headaches or numbness of the face or weakened facial muscles· People may also develop tumors in other body areas such as the brain and spinal cord· Cataracts can develop early in life causing vision difficulties or blindness eventually
Facts about Schwannomatosis *Schwannomatosis may vary greatly between patients. *Because of this, and because the population of individuals is so small and the disorder so recently characterized, these patients have been hard to definitively identify *Therefore diagnostic criteria below will continue to evolve as more cases are identified and studied
Symptoms of Schwannomatosis· Many of the symptoms of schwannomatosis overlap with NF2· Multiple schwannomas manifest throughout the body or in isolated regions· The schwannomas develop on cranial, spinal and peripheral nerves· Tumors cause chronic pain, numbness, tingling and weakness· About 1/3 of patients have segmental schwannomatosis: schwannomas are limited to a single part of the body, such as an arm, a leg or the spine· There are several cases where people with schwannomatosis have developed a vestibular schwannoma (acoustic neuroma) causing hearing loss· However vestibular schwannomas on both sides of the brain do not occur in schwannomatosis· Patients with schwannomatosis do not have learning disabilities related to the disease· Symptoms are sometimes brought on by hormonal changes such as puberty and pregnancy


Prognosis for patients with neurofibromatosis depends on the type. Surgery is often recommended to remove the tumors. Some NF1 tumors may become cancerous, and treatment may include surgery, radiation, or chemotherapy. Surgery, radiation, and chemotherapy also may be used to control or reduce the size of optic nerve tumors when vision is threatened. Some bone malformations can be corrected surgically. In most cases, symptoms of NF1 are mild, and individuals live normal and productive lives. In some cases, however, NF1 can be severely debilitating and may cause cosmetic and psychological issues.
For NF2, MRI’s, can reveal tumors as small as a few millimeters in diameter, allowing early treatment. Surgery to remove tumors completely is one option but may result in hearing loss. The course of NF2 varies greatly among individuals. In some cases of NF2, the damage to nearby vital structures, such as other cranial nerves and the brain stem, can be life-threatening.
There is no currently accepted medical treatment or drug for schwanomatosis, but surgical management is often effective. Most individuals with schwannomatosis have significant pain. In some extreme cases the pain will be severe and disabling.
Pain usually subsides when tumors are removed completely. Genetic testing is available for families with documented cases of NF1 and NF2 but such testing for schwannomatosis currently does not exist.
NF progresses differently for each person. It is hard to predict the course of the disease. A person's prognosis depends on the types and locations of tumors that he or she develops.

Sources Cited