1,25(OH)2D


1,25-dihydroxyvitamin D

123I-MIBG


123I-meta-iodobenzylguanidine

2,5-HD


2,5-hexanedione

2-D PAGE


In this technique, the proteins are separated in two dimensions (by isoelectric focusing and mass), and a pattern is achieved that places each of the 2000 proteins of a cell at a grid reference point. By reference to established databases, individual prot

2-D polyacrylamide gel electrophoresis


In this technique, the proteins are separated in two dimensions (by isoelectric focusing and mass), and a pattern is achieved that places each of the 2000 proteins of a cell at a grid reference point. By reference to established databases, individual proteins can be identified as the product of genes that have been sequenced.

2-DGE


2-dimensional gel electrophoresis

24-hour sleep-wake pattern


A person's clock hour schedule of bedtime and arise time as well as nap behavior; may also include time and duration of sleep interruptions. See Sleep-Wake Cycle; Circadian Rhythm; Sleep Log.

3,4-DAP


3,4-Diaminopyridine

3-OMD


3-O-methyldopa

5,10-Methylenetetrahydrofolate reductase


An enzyme that reduces 5,10-methylenetetrahydrofolate to 5-methyltetrahydrofolate.

5-HIAA


5-hydroxyindoleacetic acid

5-HT


5-hydroxytryptamine

5-LO


5-lipoxygenase

6-Hydroxydopamine


A potent neurotoxin.

6-OHDA


A potent neurotoxin.

6-Pyruvoyltetrahydropterin synthase deficiency


A widely variant autosomal recessive disorder of tetrahydrobiopterin metabolism resulting in reduced synthesis of biogenic amine neurotransmitters. Symptoms often include poor sucking, decreased spontaneous movements, floppiness, microcephaly, low birth weight, and early appearance of neurologic signs in the neonatal period. Variant forms of 6-pyruvoyltetrahydropterin synthase have been described in which the neurologic signs are either minor or absent. In these there are normal concentrations of homovanillic acid and 5-hydroxyindoleacetic acid in CSF, often normal EEGs, and none of the signs of abnormal serotonin and catecholamine metabolism. However, there has been a report of an atypical form of 6-pyruvoyltetrahydropterin synthetase deficiency progressing to give a central phenotype. Greatly decreased urinary biopterins and increased neopterins, as well as increased levels of phenylalanine, are seen in both forms.

A-CC


agenesis of the corpus callosum

AADC


amino acid decarboxylase

AAEE


American Association of Electromyography and Electrodiagnosis

AAV


adeno-associated virus

ABC


adenosine triphosphate-binding cassette

ABC transporter


Over 80 related proteins involved in the transport of proteins, peptides, amino acids, inorganic ions, and certain drugs in both prokaryocytes and eukaryocytes. All ABC transporters possess significant sequence identity and a similar topology, consisting of a hydrophobic domain located in the membrane and two adenosine triphosphate-binding domains on the cytoplasmic surface of the membrane. The deduced protein structure of adrenoleukodystrophy gene shares unexpected homology to ABC transporter gene. They are also referred to as traffic adenosine triphosphatases, as they require ATP as an energy source.

ABC transporters


Over 80 related proteins involved in the transport of proteins, peptides, amino acids, inorganic ions, and certain drugs in both prokaryocytes and eukaryocytes. All ABC transporters possess significant sequence identity and a similar topology, consisting of a hydrophobic domain located in the membrane and two adenosine triphosphate-binding domains on the cytoplasmic surface of the membrane. The deduced protein structure of adrenoleukodystrophy gene shares unexpected homology to ABC transporter gene. They are also referred to as traffic adenosine triphosphatases, as they require ATP as an energy source.

Abductor spasmodic dysphonia


The result of the vocal cords being pulled apart, creating a weak, breathy voice.

ABR


auditory brainstem response

ACA


anterior carotid artery

Acalculia


Acquired disorder in computational ability.

Acanthocytosis


A description of the blood film where the majority of red blood cells are acanthocytes (red blood cells with multiple spiny cytoplasmic projections).

accelerated long-term forgetting


A memory disorder in which information that is learned and retained normally over standard intervals (approximately 30 min) is forgotten at an abnormally rapid rate thereafter.

ACh


acetylcholine

AChEH


acetylcholinesterase subunits of type H

AChET


acetylcholinesterase subunits of type T

AChR


acetylcholine receptor

Achromasia


Lack of normal pigmentation of the skin, cachectic pallor.

Achromasic


Having little or no coloration after treatment with histologic stain.

Achromatic


Having little or no coloration after treatment with histologic stain.

Achromatopsia


The total lack of color perception in which all the colors of the spectrum are seen as black, grey, or white.

Acid-fast bacillus


The capacity of the bacillus, when stained with red carbol fuschin dye, to retain its red color when treated with acid.

ACNU


1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea

Acquired cytomegalovirus


Viral infection by a member of the herpes virus group that causes a wide range of diseases, transmitted by sexual contact, body secretions, blood transfusions, or organ transplants. Those who are immunodeficient are particularly susceptible.

Acrocephalopolysyndactyly


A congenital syndrome characterized by oxycephaly and brachysyndactyly of the hands, polydactyly of the feet, and mental retardation. Also known as Carpenter syndrome.

Acrocephalopolysyndactyly type I


A very rare genetic disorder characterized by abnormalities of the craniofacial area, distinctive malformations of the fingers and toes, and additional physical abnormalities. Also known as Pfeiffer syndrome, this disorder is generally accepted to be the same disorder as Noack Syndrome (Acrocephalopolysyndactyly Type I). The Acrocephalosyndactyly disorders are a group of very rare genetic disorders characterized by premature closure of the cranial sutures between certain bones of the skull, causing the top of the head to appear abnormally pointed, and webbing or fusion of certain fingers and/or toes.

Acrocephalosyndactyly type III


A condition in which there is coronal synostosis (unilateral or bilateral), facial asymmetry (particularly in individuals with unicoronal synostosis), ptosis, and characteristic appearance of the ear (small pinna with a prominent crus). Syndactyly of digits two and three of the hand is variably present. Also known as Saethre-Chotzen syndrome.

Acrocephalosyndactyly type V


A very rare genetic disorder characterized by abnormalities of the craniofacial area, distinctive malformations of the fingers and toes, and additional physical abnormalities. Also known as Pfeiffer syndrome, this disorder is generally accepted to be the same disorder as Noack Syndrome (Acrocephalopolysyndactyly Type I). The Acrocephalosyndactyly disorders are a group of very rare genetic disorders characterized by premature closure of the cranial sutures between certain bones of the skull, causing the top of the head to appear abnormally pointed, and webbing or fusion of certain fingers and/or toes.

acrocephaly


A congenital abnormality of the skull in which the top of the head assumes a conical or pointed shape because of premature closing of the lambdoid and coronal sutures. Also known as acrocephaly.

ACS


acrocallosal syndrome

ACTH


adrenocorticotropic hormone

Actigraph


A biomedical instrument for the measurement of body movement.

Actigraphs


A biomedical instrument for the measurement of body movement.

Activated protein C resistance


A hypercoagulable state, usually caused by an inherited mutation in coagulation factor V, termed "factor V Leiden."

Active myofascial trigger point


A focus of hyperirritability in a muscle of its fascia that is symptomatic with respect to pain; it causes a pattern of referred pain at rest and/or on motion that is specific for that muscle.

Active myofascial trigger points


A focus of hyperirritability in a muscle of its fascia that is symptomatic with respect to pain; it causes a pattern of referred pain at rest and/or on motion that is specific for that muscle.

Active sleep


A term used in the phylogenetic and ontogenetic literature for the stage of sleep that is considered to be equivalent to REM sleep.

Activin


One of the two gonadal glycoproteins related to transforming growth factor-beta, and is important in embryonal development.

Acute alcoholic myopathy


Acute muscle injury caused by sever alcoholic binges in alcoholics, leading to swollen painful muscles and rhabdomyolysis.

Acute disseminated encephalomyelitis


Generally used to describe an acute, severe, monophasic event following vaccination of viral infection by 6 to 24 days. The process is multifocal and demyelinating and may be hemorrhagic.

Acute multiple sclerosis, Marburg variant


Part of the spectrum of multiple sclerosis initially described by Marburg in 1906, which included examples of lesions with bands of preserved myelin and disrupted myelin.

ACY1


Aminoacylase 1

ADC


apparent diffusion coefficient

Add-on trial


Clinical trials in which test medications are added to already present regimens.

Add-on trials


Clinical trials in which test medications are added to already present regimens.

Adductor spasmodic dysphonia


The result of the vocal cords' hyperadducting, creating a strained, choked voice.

ADEM


acute disseminated encephalomyelitis

ADH


antidiuretic hormone

ADHAPS


alkyl-dihydroxyacetonephosphate synthase

ADHD


attention deficit hyperactivity disorder

ADP


adenosine 5'diphosphate

adrenoleukodystrophy protein


An ATP-binding cassette (ABC) transporter in the human peroxisome membrane. It is defective in X chromosome-linked adrenoleukodystrophy.

Affective disorder


Any mental disorder in which a disturbance of the affect is predominant (eg, major depression, bipolar affective disorder).

aFP


alpha-fetoprotein

AgNOR


silver-staining nucleolar organizer region

Agnosia


Failure to recognize environmental stimuli despite intact sensory function.

Agrammatism


Failure to use grammatical rules, typified by producing mainly nouns and verbs, without modifying them according to their functions in sentences.

Agraphesthesia


The inability to name isolated letters or numerals traced on the skin, usually on the palm, without viewing.

Agraphia


Acquired inability to write due to cognitive dysfunction.

Agraphic acalculia


Disturbance in calculation abilities resulting from a defect in the normal ability to write.

AICA


anterior inferior cerebellar artery

AIDP


acute inflammatory demyelinating polyradiculoneuropathy

Air conduction


Transmission of sound to the cochlea through air to the external and middle ears.

Akathisia


Inner sense of restlessness relieved by volitional movement of the leg.

Akinesia


Absence of, but more accurately the paucity of, spontaneous unconscious movements.

Alagille syndrome


A genetic disorder that affects the liver, heart, and other systems of the body. Problems associated with the disorder generally become evident in infancy or early childhood. The disorder is inherited in an autosomal dominant pattern, and the estimated prevalence is 1 in every 70,000 live births. Also known as Alagille syndrome.

Albright hereditary osteodystrophy


A genetic disorder that resembles hypoparathyroidism (lowered levels of parathyroid hormone) but is caused by a lack of response to parathyroid hormone rather than a deficiency in the hormone itself. Also known as Albright hereditary osteodystrophy.

Albright’s hereditary osteodystrophy


A genetic disorder that resembles hypoparathyroidism (lowered levels of parathyroid hormone) but is caused by a lack of response to parathyroid hormone rather than a deficiency in the hormone itself. Also known as Albright hereditary osteodystrophy.

Alcohol-related neurodevelopmental disorder


A disorder of neurodevelopment due to prenatal exposure to alcohol. In this disorder, the growth retardation and facial characteristics of fetal alcohol syndrome are not present. The neurodevelopmental abnormalities most often include deficits in attention and learning.

ALDP


Adrenoleukodystrophy protein

ALDRP


Adrenoleukodystrophy-related protein

Alexic acalculia


Disturbance in calculation abilities resulting from a defect in the normal ability to read.

Alkaptonuria


A rare inherited disorder of metabolism, characterized by urine that turns black when exposed to air. Another characteristic is the development of arthritis in adulthood. Also known as ochronosis or homogentisic acid oxidase deficiency.

Allele


One member of a pair or series of genes that occupies a specific location on a specific chromosome.

Alleles


One member of a pair or series of genes that occupies a specific location on a specific chromosome.

Allodynia


(From allo, other, and dynia, tenderness) Pain due to a stimulus that does not normally provoke pain.

Alpha activity


An alpha EEG wave or sequence of waves with a frequency of 8-13 Hz.

Alpha infiltration


A brief superimposition of EEG alpha activity on sleep activities during a stage of sleep.

Alpha insertion


A brief superimposition of EEG alpha activity on sleep activities during a stage of sleep.

Alpha interruption


A brief superimposition of EEG alpha activity on sleep activities during a stage of sleep.

Alpha intrusion


A brief superimposition of EEG alpha activity on sleep activities during a stage of sleep.

Alpha rhythm


An EEG rhythm with a frequency of 8-13 Hz in human adults, which is most prominent over the parieto-occipital cortex when the eyes are closed. The rhythm is blocked by eye opening or other arousing stimuli. It is indicative of the awake state in most normal individuals. It is most consistent and predominant during relaxed wakefulness, particularly with reduction of visual input. The amplitude is variable, but typically is below 50 'V in the adult. The alpha rhythm of an individual usually slows by 0.5-1.5 Hz and becomes more diffuse during drowsiness. The frequency range also varies with age; it is slower in children and older age-groups relative to young and middle-aged adults.

Alpha rhythms


An EEG rhythm with a frequency of 8-13 Hz in human adults, which is most prominent over the parieto-occipital cortex when the eyes are closed. The rhythm is blocked by eye opening or other arousing stimuli. It is indicative of the awake state in most normal individuals. It is most consistent and predominant during relaxed wakefulness, particularly with reduction of visual input. The amplitude is variable, but typically is below 50 'V in the adult. The alpha rhythm of an individual usually slows by 0.5-1.5 Hz and becomes more diffuse during drowsiness. The frequency range also varies with age; it is slower in children and older age-groups relative to young and middle-aged adults.

Alpha sleep


Sleep in which alpha activity occurs during most, if not all, sleep stages.