Wednesday, March 13, 2013

LAMC2 gene cause JEB


More than 30 mutations in the LAMC2 gene have been identified in people with Junctional Epidermolysis Bullosa (JEB). The more severe form of the disease ‘Herlitz JEB’ — results from mutations that severely disrupt the production of functional ‘laminin 332’. Most of these mutations lead to a premature stop signal in the instructions for making the gamma (g) subunit of laminin 332, which prevents the assembly of this protein. Without laminin 332, the epidermis is weakly connected to the underlying layers of skin. Friction even minor trauma (such as rubbing or scratching) can cause the skin layers to separate, leading to the formation of blisters. Infants with Herlitz JEB develop widespread blistering that causes life-threatening complications.

Other LAMC2 gene mutations cause the milder form of JEB  ‘non-Herlitz JEB’. Some of these mutations alter single protein building blocks (amino acids) in the gamma (g) subunit of laminin 332. Others add or delete a small number of amino acids in the gamma (g) subunit or change the way the gene's instructions are used to make the subunit. The genetic changes responsible for non-Herlitz JEB usually lead to the production of a laminin 332 protein that retains some of its function. Affected individuals experience blistering, but it may be limited to the hands, feet, knees, and elbows and often improves after the newborn period.




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