Glossary - S to V

An unwanted effect of a drug. Examples include nausea, headaches etc.

A type of antioxidant enzyme that normally protects cells from damaging substances. 20% of people with familial MND (that which is passed down through generations in a family) have a mutation (mistake) in the gene that holds the instructions to make SOD1.

Involuntary contraction of a muscle or group of muscles.

Stiffness and rigidity caused by involuntary contraction of a muscle.

Part of the Central Nervous System running from the base of the skull down through the spine. It contains nerves carrying messages from the brain out to the body and from the body back to the brain.  

The term used for MND cases where there is no family history of the disease. It accounts for 90 - 95% of all cases. Compare familial MND.

Cells that have not yet become specialised to perform a particular function. They therefore have the potential to become any one of several types of cell; scientists believe that eventually they may be able to coax stem cells to become whatever type of cell a patient needs, for example motor neurones. Stem cells may also be used in other ways; for example they may be capable of nourishing existing nerves and could possibly also be used to deliver drugs. However, stem cell research is at a very early stage. See also embryonic stem cells, umbilical cord blood stem cells, iPS (induced pluripotent stem) cells.

Injection of a drug just under the skin.

Variations of genes that may increase the risk of developing sporadic MND, which occurs where there is no family history of the disease. On their own, these variations do not cause MND; the disease will occur because of a combination of genetic, lifestyle and environmental factors.

A tiny gap between one nerve and the next. Signals are passed across the gap by neurotransmitters.

TDP-43 is a protein that is present in abnormal clumps in motor neurones that are affected by MND. It is now known that this protein can damage the motor neurones of people who have MND.

A technique used to create embryonic stem cells for research. It involves removing the DNA from an unfertilised egg and replacing it with the DNA from an adult cell (usually a skin cell). The egg is then triggered to begin dividing to form an embryo from which embryonic stem cells can be obtained. These cells will be genetically identical to the adult skin cells that provided the DNA.  

A group of specialised cells that perform a similar function e.g. a group of muscle cells make up muscle tissue

Refers to plants and animals (such as mice) that have been changed by the addition of genetic material from another species. Transgenic mice to which the mutated SOD1 gene has been added are used as an animal model for MND research.

The process by which potential new treatments are tested to ensure that they are safe and effective. The process can take as long as several years.

A substance that nourishes cells. See also neurotrophic factor.

Nerve cells that carry messages from the brain to the spinal cord. Compare lower motor neurones.

A "vehicle", such as a modified virus, used to deliver genetic material into the body for gene therapy.

Regulates blood supply in the body but may also be a neurotrophic factor (nerve-nourishing substance) that could play a role in maintaining motor neurone health. Certain variations in the gene for VEGF are seen more often in people with MND than in the general population. See also ANG gene and susceptibility genes.