• A Neurofibromatosis is an A.D. genetically-inherited disorder in which the nerve tissue grows abnormally to form tumors (neurofibromas) that may be benign or may cause serious damage by compressing nerves and other tissues.
• Affects all neural crest cells (Schwann cells, melanocytes and endoneurial fibroblasts).
• Melanocytes also function abnormally in this disease, resulting in disordered skin pigmentation and café au lait spots.
• Approximately half of cases are due to de novo mutations and no other affected family members are seen.• It affects males and females equally.
Neurofibromatosis type 1 (NF 1)• Also known as "von Recklinghausen disease“• Most common form of NF (90%)• It occurs following the mutation of neurofibromin on chromosome 17q11.2.
The diagnosis of NF1 is made if any two of the following 7 criteria are met:1. Two or more neurofibromas on or under the skin, or one plexiform neurofibroma (a large cluster of tumors involving multiple nerves);
2.Freckling of the groin or the axilla 2- 3mm in diam .
3 .Café au lait spots:(Hallmark of NF) - Six or more measuring 5 mm in greatest diameter in prepubertal individuals and over 15 mm in greatest diameter in postpubertal individuals.
4. Lisch nodules (hamartomas of iris), freckling in the iris- 2 or more
5. Tumors on the optic nerve, also known as an optic glioma
6. A distinctive osseous lesion such as sphenoid dysplasia or cortical thinning of long bones with or without pseudoarthrosis.
7. A first degree relative with NF 1 whose diagnosis was based upon these criteria.
• Macrocephaly in 30-50% of the pediatric population without any hydrocephalus• Epilepsy (seizures)• Juvenile posterior lenticular opacity• Scoliosis with or without kyphosis
• NF 1 also increases the risk of tumor development, particularly, meningiomas, glio mas and pheochromocytomas.• hydrocoele• early puberty
Neurofibromatosis type 2 (NF 2)• Also called "central neurofibromatosis“• Is results from mutation of the merlin (also known as "schwannomin") in chromosome 22q12.i.e NF2 gene• It accounts for only 10% of all cases of NF
• The disorder manifests in the following fashion:1. Bilateral acoustic neuromas :( tumors of the vestibulocochlear nerve or cranial nerve 8 (CN VIII) also known as schwannoma), the hallmark of NF 2 is hearing loss due to acoustic schwanoma.
2. – headache – balance problems, and peripheral vertigo due to schwannoma and involvement of the inner ear – facial weakness/paralysis due to involvement or compression of the facial nerve. – brain tumors, as well as spinal tumors. – deafness and tinnitus
• NF 2 increases the risk of meningiomas and ependymomas.
Schwannomatosis• Schwannomatosis - mutation in both chromosomes 17 and 22• The schwannomas develop on cranial, spinal and peripheral nerves.• Chronic pain, and sometimes numbness, tingling and weakness• About 1/3 of patients have segmental schwannomatosis, i.e.schwannomas are limited to a single part of the body, such as an arm, a leg or the spine.
• Unlike the other forms of NF, the schwannomas do not develop on vestibular nerves, and as a result, no loss of hearing is associated with schwannomatosis.• Patients with schwannomatosis do not have learning disabilities related to the disorder.
Other variants• Neurofibromatosis type 3• Neurofibromatosis type 4• Neurofibromatosis type 5
• Neurofibromatosis is considered a member of the neurocutaneous syndromes (phakomatoses).• The phakomatoses also include Tuberous sclerosis, Sturge-Weber syndroms , Von Hippel-Lindau disease, Ataxia telengectesia,
Signs and symptoms• Morbidity is often a result of plexiform neuromas, optic gliomas, or acoustic neuromas, but mortality can also be associated with malignant transformation of the neuromas, such as neurofibrosarcomas
• Learning disabilities or cognitive deficit• Development of Epilepsy in affected individuals• Increases the risk of leukemia particularly in children.• Deafness• Neoplasms- pheochromocytoma, neurofibrosarcoma (malignant degeneration of neurofibromas), Wilms tumour, rhabdomyosarcoma, juvenile pilocytic astrocytoma, carcinoid tumour, leiyomyoma, leiyomyosarcoma
Diagnosis• Fetus-Chorionic villus sampling or amniocentesis can be used• MRI• Slit lamp
Treatment• There is no cure for the condition so the only therapy for patients with neurofibromatosis is to manage symptoms or complications.• Surgery may be needed when the tumors compress organs or other structures.• Less than 10% of people with neurofibromatosis develop cancerous growths; in these cases, chemotherapy may be successful.
• Genetic screening and counselling for families with neurofibromatosis.
Cases• In May 2011, a case was reported in the United Kingdom in which a 15-month-old child who turned out to have Neurofibromatosis type I was misdiagnosed as being abused under the assumption that the mother had Münchausen syndrome, because the child gained weight while in hospital and lost weight while at home. The child was placed in foster care for 6 months and then returned to his parents after he was correctly diagnosed.