<unk>  type I is caused by a mutation on chromosome 17 encoding a cytoplasmic protein known as neurofibromin. This protein is a tumor suppressor and therefore serves as a signal regulator of cell proliferation and differentiation. A dysfunction or lack of neurofibromin can affect regulation, and cause uncontrolled cell proliferation, leading to the tumors (neurofibromas) that characterize<unk> 1. The neurofibromas caused by<unk>  consist of Schwann cells, fibroblasts, perineuronal cells, mast cells and axons embedded in an extracellular matrix. Another function of neurofibromin is to bind to microtubules that play a role in the release of adenylyl cyclase and its activity. Adenylyl cyclase plays an essential role in cognition. Neurofibromin's role in the activity of adenylyl cyclase explains why patients with<unk>  experience cognitive impairment.<unk>  type II is caused by a mutation on chromosome 22. The mutation falls on the<unk> 2 tumor suppressor gene. The gene normally encodes a cytoplasmic protein known as merlin. The normal function of merlin is to regulate the activity of multiple growth factors, the mutated copy of the gene leads to merlin's loss of function. The loss of function leads to increased activity of growth factors normally regulated by merlin, leading to the formation of the tumors associated with<unk> 2. Schwannomatosis is caused by a mutation on the SMARCB1 gene. This gene is located near the<unk> 2 tumor suppressor gene leading to the thought that schwannomatosis and<unk> 2 were the same condition. The two conditions show different mutations on two different genes. The normal function of the SMARCB1 gene is to encode a protein called SMARCB1 that is part of a larger protein complex whose function is not completely understood. The complex including SMARCB1 plays a role in tumor suppression. The mutation of the SMARCB1 gene causes a loss of function in the complex leading to the formation of tumors indicative of schwannomatosis.
Neurofibromatosis
Tuberous sclerosis
Fox–Fordyce disease
Ollier disease
Irlen syndrome
Progeria
Fabry disease
Degos disease