Clinical Terminology A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Autosomal dominant: A mode of genetic inheritance in which one copy of a particular gene is always expressed and there is a 50% chance of passing this gene on to the next generation with every pregnancy.

Chronic sleep deprivation: A disorder caused by repeated sleep disturbances that lead to inadequate amounts of sleep. Chronic sleep deprivation can have a strong impact on daily activities, affecting mood, energy, and the ability to concentrate.

D2 receptor: A G-protein coupled neuronal cell receptor that binds directly to the neurotransmitter dopamine. There are 5 subtypes of dopamine receptor currently known, numbered D1 to D5.

Dopaminergic system: A system of neurotransmission that uses the catecholamine neurotransmitter dopamine, found primarily in the central nervous system.

Dysesthesia: An abnormal or uncomfortable sensation due to neurological dysfunction.

Familial aggregation: The propensity for a particular trait or disease to occur within families in such a way as to suggest genetic involvement.

Ferritin: A protein that transports and stores iron. Serum ferritin levels can be measured so as to assess reliably iron levels in the body, independent of dietary fluctuations.

Ferroportin: A molecule that transports iron out of cells due to the fact that iron can not easily cross lipid-rich cellular membranes.

Idiopathic restless legs syndrome (RLS): Primary RLS that occurs without any known cause and is not the result of comorbidity.

International RLS Study Group: An international group of investigators chosen for their significant contributions to the field of restless legs syndrome research. This group has played a critical role in defining the essential criteria for RLS diagnosis.

Myoclonus: A rapid and brief involuntary muscle spasm.

Narcolepsy: A neurological condition characterized by sudden uncontrollable episodes of deep sleep.

Neuroleptics: A group of antipsychotic medications that consist of dopamine antagonists.

Neuromelanin cells: Dopaminergic neurons that contain a byproduct of dopamine metabolism that is believed to bind iron.

Nigostriatal: A pathway consisting of dopaminergic neurons that join the corpus striatum (made up of the caudate and putamen nuclei) to the substantia nigra. This neurological pathway is involved in controlling voluntary movement.

Paresthesia: A spontaneously occurring abnormal sensation that may include tingling, burning, or cramp-like sensations.

Positron emission tomography: An imaging technique that uses a positron emitting radioisotope to measure brain activity or metabolism indirectly by visualizing cerebral blood flow.

Pruritus: The medical term for the symptom of itching.

Restless legs syndrome (RLS): A sensorimotor disorder characterized by unpleasant sensations that occur primarily in the legs. These sensations lead to an overwhelming desire to move the affected limb in an effort to ease discomfort. The effects of RLS are associated with sleep disturbance, daytime exhaustion, and diminished quality of life.

Secondary restless legs syndrome (RLS): Restless legs syndrome symptoms that occur due to a secondary condition such as pregnancy, anemia, or iron deficiency. Secondary RLS usually will go away once the underlying condition has been treated.

Sensorimotor: A term used to describe the combination and interaction of sensory and motor effects.

Substantia nigra: An area of the brain rich in neuromelanin cells involved in dopamine production and sensorimotor control.

Susceptibility loci: The possible location of a gene within a chromosome.

Transferrin: A protein that transports iron within the bloodstream.

Vertebral disc disease: A condition in which the intervertebral disc between 2 vertebrae herniates and compresses the spinal cord.