The genes people inherit contribute to their susceptibility for developing an autoimmune disease. Certain diseases such as psoriasis can occur among several members of the same family. This suggests that a specific gene or set of genes predisposes a family member to psoriasis.
Motor neurone disease occurs when specialist nerve cells (motor neurones) in the brain and spinal cord progressively lose their function. It's not clear why this happens. In most cases, a person with motor neurone disease won't have a family history of the condition. This is known as sporadic motor neurone disease.
Adult onset progressive motor neuron disease involving degeneration and scarring (gliosis) of the motor neurons in lateral spinal cord, brainstem, and cerebral cortex (UMN), peripheral motor nerves (LMN), and muscle atrophy as a result.