The majority of<unk>  cases are caused by a point mutation at amino acid 816 of the proto-oncogene c-kit. c-kit is a transmembrane protein which, when bound to Mast Cell Growth Factor (MCGF), signals the cell to divide. Mutations in position 816 of c-kit can result in a constant division signal being sent to the mast cells, resulting in abnormal proliferation. Different mutations have been linked to different onset times of the disease. For example, the Asp816Phe and Asp816Val mutations (the aspartate normally at position 816 in the c-kit protein has been replaced with phenylalanine or valine respectively) have been associated with early manifestation of the disease (mean age of onset: 1.3 and 5.9 months respectively). The c-kit gene is encoded on the q12 locus of chromosome 4. Irritants Several factors can worsen the symptoms of<unk> : * Emotional stress * Physical stimuli such as heat, friction, and excessive exercise * Bacterial toxins * Venom * Eye drops containing dextran * NSAIDs * Alcohol * Morphine The classification of NSAIDs can be disputed. Aspirin, for example, causes the mast cells to degranulate, releasing histamines and causing symptoms to flare. However, daily intake of 81 mg aspirin may keep the mast cells degranulated. Thus, while symptoms may be worsened at first, they can get better as the mast cells are unable to recharge with histamine.
Urticaria pigmentosa
Ichthyosis acquisita
Lamellar ichthyosis
Phytophotodermatitis
Ichthyosis bullosa of Siemens
Striate keratoderma
Dermatopathia pigmentosa reticularis
Ichthyosis vulgaris