A substance, such as pollen, that causes an allergy. - Though allergens are not harmful themselves, when they are combined with certain antibodies, a reaction (i.e. the allergy) liberates substances that damage body cells and tissues.. A substance, such as pollen, that causes an allergy. [German. : , allergy; see allergy +. , -gen (from French. ; see-gen).]. alâ²lerÂ·genâ²ic (-jÄnâ²Ä­k) adj.
A Honor Society of Nursing (STTI) answered. Prognosis varies depending on the type of motor neuron disease (MND) and the age of onset. Some MNDs, such as Post-polio syndrome (PLS), are not fatal and progress slowly.People with Spinal muscular atrophy (SMA) may appear to be stable for long periods, but improvement should not be expected.ome MNDs, such as Post-polio syndrome (PLS), are not fatal and progress slowly. People with Spinal muscular atrophy (SMA) may appear to be stable for long periods, but improvement should not be expected.
2 In most cases, MND is steadily progressive and an average course is about four years. However, the disease may be very variable in length, and some patients have lived for 10-20 years. In a few cases progression of the disease has actually halted spontaneously, but this is rare.ecause MND is a progressive disease, the muscular weakness becomes worse with time. The patient may eventually require a wheelchair because of leg and trunk weakness, and become generally immobile. At some stage in the disease the patient will suffer from âbulbarâ symptoms.