Glossary - E to H

The ability of a drug to produce the desired effect.

A laboratory technique that uses electric shocks to open the pores of cells to allow substances into them that would otherwise be blocked. Examples of such substances include DNA and drugs.

Stem cells found during the very earliest stages of development; they go on to develop into an embryo. Embryonic stem cells have the potential to grow into any type of cell.

Emotional instability, a tendency to change mood very quickly and laugh or cry very easily.

A protein that increase the rate of a chemical reaction in the body.

The study of the patterns, causes and control of disease in groups of people.

A possible cause of motor neurone destruction in MND. It occurs when the signals between nerves become too strong because there is too much of a particular neurotransmitter known as glutamate, which relays impulses from one nerve cell to the next.

MND caused by genetic damage, or mutation, which is passed down from one generation to another. Around 10% of all MND cases are familial MND. Compare sporadic MND. Find out more about how much of MND is inherited.

Muscle twitching caused by small involuntary contractions of muscle fibres; can be a symptom of MND but also experienced by many otherwise healthy individuals.

Hilghly reactive toxic molecules that are formed during energy production within a cell. They are usually made safe by antioxidants.

FUS - short for 'Fused in Sarcoma' is a protein that is present in motor neurones that are affected by a rare inherited form of MND that accounts for 3-5% of cases of familial MND.

• Second new gene discovered in less than a year

A cluster of nerve cell bodies.

A type of neurotrophic factor (nerve-nourishing substance) that is made by nervous system support cells known as glial cells.

A unit of biological information, composed of DNA, which holds the instructions to make a particular protein. Genes are passed from one generation to the next.

Treatment of a disease by introducing a replacement gene into a cell. The new gene may be used to replace a function that is missing because of a defective gene. Alternatively, gene therapy may put extra copies of an existing gene into a cell to boost production of a helpful substance.

All of the genetic information posessed by a particular living thing.

Cells found in the central nervous system that support and maintain nerve cells.

An amino acid that functions as a neurotransmitter (a chemical that carries impulses between one nerve and the next) in the central nervous system.