The region of DNA responsible for this variability is also involved in Parkinsons disease, giving rise to current speculation that the two disorders may be linked at the biochemical level. Mechanism
Most leprosy complications are the result of nerve damage. The nerve damage occurs from direct invasion by the M. leprae bacteria and a persons immune response resulting in inflammation. The molecular mechanism underlying how M. leprae produces the symptoms of leprosy is not clear, but M. leprae has been shown to bind to Schwann cells, which may lead to nerve injury including demyelination and a loss of nerve function (specifically a loss of axonal conductance). Numerous molecular mechanisms have been associated with this nerve damage including the presence of a laminin-binding protein and the glycoconjugate (PGL-1) on the surface of M. leprae that can bind to laminin on peripheral nerves.As part of the human immune response, white blood cell-derived macrophages may engulf M. leprae by phagocytosis.In the initial stages, small sensory and autonomic nerve fibers in the skin of a person with leprosy are damaged. This damage usually results in hair loss to the area, a loss of the ability to sweat, and numbness (decreased ability to detect sensations such as temperature and touch). Further peripheral nerve damage may result in skin dryness, more numbness, and muscle weaknesses or paralysis in the area affected. The skin can crack and if the skin injuries are not carefully cared for, there is a risk for a secondary infection that can lead to more severe damage.
This molecular test alone is not sufficient to diagnose a person, but this approach may be used to identify someone who is at high risk of developing or transmitting leprosy such as those with few lesions or an atypical clinical presentation. Classification
Several different approaches for classifying leprosy exist. There are similarities between the classification approaches. The World Health Organization system distinguishes "paucibacillary" and "multibacillary" based upon the proliferation of bacteria. ("pauci-" refers to a low quantity.) The Ridley-Jopling scale provides five gradations. The ICD-10, though developed by the WHO, uses Ridley-Jopling and not the WHO system. It also adds an indeterminate ("I") entry. In MeSH, three groupings are used. Leprosy may also occur with only neural involvement, without skin lesions. Prevention
Early detection of the disease is important, since physical and neurological damage may be irreversible even if cured. Medications can decrease the risk of those living with people who have leprosy from acquiring the disease and likely those with whom people with leprosy come into contact outside the home. The WHO recommends that preventive medicine be given to people who are in close contact with someone who has leprosy. The suggested preventive treatment is a single dose of rifampicin (SDR) in adults and children over 2 years old who do not already have leprosy or tuberculosis.