A |
| Addison’s disease |
Disease resulting from deficiency in the secretion of adrenocortical hormones. |
| allele |
One of two or more different genes containing specific inheritable characteristics that occupy corresponding positions (loci) on paired chromosomes. |
| amyloid |
A protein-polysaccharide complex having starchlike characteristics produced and deposited in tissues during certain pathological states. |
| amyloid beta (AB) |
A free-floating protein in the CSF; in Alzheimer’s patients, the AB42 form accumulates in the central nervous system and forms amyloid plaques in the brain. |
| anticipation |
The phenomenon of increased severity and earlier onset of genetic disease when a mutation is transmitted from one generation to the next. |
| ApoE genotype |
A susceptibility gene that contributes to the risk of developing Alzheimer’s disease after age 65 in demented individuals. |
| areflexia |
Absence of reflexes. |
| arthrogryposis congenita multiplex |
Congenital generalized fixation of the ankylosis of the joints; may be due to a variety of changes in the spinal cord, muscles, or connective tissue. |
| arthrogyrposis |
Fixation of a joint in a flexed or contracted position; may be due to adhesions in or around the joint. |
| asymmetric |
Referring to lack of symmetry; usually affecting only one side of the body. |
| ataxia |
Defective muscular coordination, esp. that manifested when voluntary muscular movements are attempted. |
| autosomal dominant |
Individuals possessing one copy of a mutation on an autosomal chromosome will be affected. |
| autosomal recessive |
Individuals possessing two copies of a mutation on an autosomal chromosome will be affected. |
| axonal |
Referring to an axon, which is a process of a neuron that conducts impulses away from the cell body. |
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B |
| base pair |
In the double-stranded helical arrangement of DNA, the connecting chemicals (i.e., base pairs) are either an adenine-thymine pair or a guanine-cytosine pair. |
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C |
| cardiomegaly |
Enlargement of the heart. |
| cardiomyopathy |
Disease of the myocardium, esp. that caused by primary disease of the heart muscle. |
| carnitine deficiency |
A deficiency of a chemical, gamma-trimethylamine-beta-hydroxybutyrate, important in metabolizing palmitic and steric acids. |
| Carpal tunnel syndrome |
Pain or numbness that affects some part of the median nerve distribution of the hand (the palmar side of the thumb, the index finger, the radial half of the ring finger, and the radial half of the palm) and may radiate into the arm. There may be a history |
| caudate nucleus |
A comma-shaped mass of gray matter forming part of the corpus striatum. It constitutes part of the basal ganglia. SYN:intraventricular nucleus |
| cerebellum |
The portion of the brain forming the largest segment of the rhombencephalon. It lies dorsal to the pons and medulla oblongata, overhanging the latter. It consists of two lateral cerebellar hemispheres and a narrow medial portion, the vermis. It is conne |
| cerebrospinal fluid (CSF) |
A water cushion protecting the brain and spinal cord from physical impact. Shrinkage or expansion of the cranial contents is usually balanced quickly by an increase or decrease in the amount of this fluid. |
| cervical myelopathy |
Any pathological condition of the spinal cord involving the cervical or lumbar vertebrae and related tissues. |
| chorea |
A nervous condition marked by involuntary muscular twitching in the limbs or facial muscles. |
| creatine kinase |
An enzyme present in skeletal muscle, cardiac muscle, and the brain. It catalyzes the high energy phosphate between creatine and phosphocreatine and between adenosine diphosphate (ADP) and adenosine triophosphate (ATP). |
| Creutzfeldt-Jakob disease |
A central nervous system disease that causes presenile dementia, myoclonus, and distinctive electroencephalographic changes. The causative organism is assumed to be a prion. |
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D |
| deletion |
A loss of DNA sequence that can range from a single base pair within a gene to a large part of the chromosome. |
| demyelination |
Destruction or removal of the myelin sheath of nerve tissue. |
| diplopia |
Double vision, which may be monocular. |
| disomy† |
An abnormal chromosome represented twice in a single cell. |
| distal |
Farthest from the center, from the medial line, or from the trunk; opposed to proximal. |
| dorsiflexion |
Movement of a part at a joint to bend the part toward the dorsum, or posterior aspect of the body. |
| duplication† |
Inclusion of two copies of the same genetic material in a genome. A chromosome aberration resulting from unequal crossing over or exchange of segments between two homologous chromosomes. |
| dysarthria |
Difficult and defective speech due to impairment of the tongue or other muscles essential to speech. Mental function is intact. |
| dysphagia |
Inability to swallow or difficulty in swallowing. |
| dystonia |
Prolonged muscle contractions that may cause twisting and repetitive movements or abnormal posture. |
| dystrophic† |
Relating to dystrophy, which are progressive changes that may result from defective nutrition of a tissue or organ. |
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E |
| encephalomyelitis |
Acute inflammation of the brain and spinal cord. |
| encephalopathy |
Any dysfunction of the brain. |
| etiology |
The cause of disease. |
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F |
| fasciculations |
Involuntary contractions or twitching of muscle fibers, visible under the skin. |
| focal compression |
A squeezing together [of a nerve in a localized area]; the condition of being pressed together. |
| frameshift |
A change in the reading frame of the gene (this occurs if the number of base pairs in the deletion or insertion is not a multiple of three). In most cases, the altered reading frame results in a truncated or elongated protein. |
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G |
| genomic imprinting |
An occurrence when the expression of a gene is affected by the parental origin. |
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H |
| hepatomegaly |
An enlargement of the liver. |
| hilar |
Referring to a depression or recess at the exit or entrance of a duct into a gland or of nerves and vessels into an organ. |
| hypogonadism |
Defective internal secretion of the gonads. |
| hyporeflexia |
A diminished function of the reflexes. |
| hypotonia |
Loss of tonicity of the muscles or intraocular pressure. |
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I |
| ichthyosis |
A condition in which the skin is dry and scaly, resembling fish skin. |
| idiopathic |
Pertaining to conditions without clear pathogenesis, or disease without recognizable cause, as of spontaneous origin. |
| innervate |
To stimulate a part, as the nerve supply of an organ. |
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L |
| lactic acidosis |
An accumulation of lactic acid in the blood, whatever the cause. Any disease that leads to tissue hypoxia, exercise, hyperventilation, or some drugs (e.g. oral hypoglycemic agents) may cause this condition. |
| leukodystrophy |
An incurable disease of the central nervous system in which the formation of the myelin is abnormal. This may be due to a specific biochemical defect. |
| limbic encephalitis |
Inflammation of the limbic system of the brain. |
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M |
| macroglossia |
Hypertrophied condition of the tongue; a congenital disorder. |
| maternally inherited disorder |
A disorder that is inherited from the mother’s genome or the maternal side of a family. |
| mediastinal |
Referring to the mass of organs and tissues separating the lungs. |
| mediastinoscopy |
Endoscopic examination of the mediastinum. |
| mesovarium |
The portion of the peritoneal fold that connects the anterior border of the ovary to the posterior layer of the broad ligament. |
| metachromatic leukodystrophy |
A type of hereditary leukodystrophy caused by a deficiency of the enzyme cerebroside sulfatase, an enzyme that is essential for the degradation of sulfatide. |
| mosaicism |
The presence of mutated as well as normal alleles in the cells, which produce gametes. |
| M-protein (or monoclonal immunoglobulin)†,†† |
A protein associated with peripheral neuropathy or monoclonal gammopathies. Monoclonal proteins have been found in 10% of patients with idiopathic polyneuropathies, a prevalence six to 10 times that in the general population. The prevalance of monoclonal |
| Multiple sclerosis |
A chronic autoimmune inflammatory disease of the central nervous system marked by intermittent damage to the myelin sheath that covers the nerve cell axons. Visual changes and muscle weakness occur often and have no consistent pattern; as the disease progr |
| myoclonus |
Twitching or clonic spasm of a muscle or group of muscles. |
| myoglobinuria |
Myoglobin in the urine. It may occur following muscular activity, trauma, or as a result of a deficiency of muscle phosphorylase. |
| myopathic |
Any disease or abnormal condition related to striated muscle. |
| myotonia |
Tonic spasm of a muscle or temporary rigidity after muscular contraction. |
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N |
| neoplasm |
A new and abnormal formation of tissue, as a tumor or growth. It serves no useful function, but grows at the expense of the healthy organism. |
| neuralgia |
Severe sharp pain occurring along the course of a nerve. |
| neuritis |
Inflammation of a nerve, usually associated with a degenerative process. |
| neuroblastoma |
A malignant hemorrhagic tumor composed principally of cells resembling neuroblasts that give rise to cells of the sympathetic system, esp. adrenal medulla. This condition occurs chiefly in infants and children. |
| neurofibrillary tangles |
Intraneuronal structures formed from paired helical filaments, which are composed of abnormally phosphorylated tau proteins, wound together in a double helix. |
| neuropathy |
Any disease of the nerves. |
| nystagmus |
Constant involuntary, cyclical movement of the eyeball in any direction. |
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O |
| onconeuronal antigens |
Antigens, common to both neoplastic and normal neural tissue, that are recognized as foreign and lead to autoantibodies attacking both the tumor as well as portions of the nervous system. |
| opsoclonus |
Conjugate irregular and nonrhythmical jerking movements of the eyes. |
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P |
| paired helical filaments |
Abnormally phosphorylated tau proteins. |
| paraparesis |
Partial paralysis affecting the lower limbs. |
| paraparetic† |
Relating to paraparesis. A person with paraparesis. |
| paroxysm |
A sudden, periodic attack or recurrence of symptoms of a disease. |
| pathognomonic |
Indicative of a disease, esp. its characteristic symptoms. |
| penetrance |
The frequency of manifestation of a hereditary condition in individuals. |
| peroneal palsy |
Paralysis of the fibula or lateral side of the leg. |
| pes cavus |
An abnormal hollowness or concavity of the sole of the foot; an excessively high longitudinal arch in the foot. |
| phytanic acid |
An acid that accumulates in the serum and tissues in Refsum’s disease and attributed to the hereditary absence of phytanate alpha-oxidase. |
| pigmentary retinopathy |
See retinitis pigmentosa |
| plaques† |
A spherical mass comprised primarily of amyloid fibrils and interwoven neuronal processes, frequently, although not exclusively, observed in Alzheimer’s disease. |
| point mutation |
Substitution of one nucleotide for another within a gene resulting in a missense, nonsense, or splice mutation. |
| pontocerebellar atrophy† |
Progressive neurologic disease characterized by loss of neurons in the cerebellar cortex and the basis pontis. It can result in ataxia, tremor, involuntary movement, and dysarthria. |
| progressive external ophthalmoplegia |
A specific type of slowly worsening weakness of the ocular muscles, usually associated with a pigmentary retinopathy. |
| pseudobulbar palsy† |
Supranuclear paralysis of the bulbar nerves. |
| ptosis |
Dropping or drooping of an organ or part, as the upper eyelid from paralysis. |
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R |
| radiculitis |
Inflammation of the spinal nerve roots, accompanied by pain and hyperesthesia. |
| retinitis pigmentosa |
A chronic progressive disease that has its onset in early childhood. It is marked by degeneration of the retinal epithelium, esp. the rods, without inflammation; atrophy of the optic nerve; and widespread pigmentary changes in the retina. An early sympto |
| Romberg sign |
The inability to maintain body balance when the eyes are shut and the feet are close together. The sign is positive if the patient sways and falls when the eyes are closed. This is seen in sensory ataxia. |
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S |
| saccadic |
Pertaining to rapid intermittent movements, esp. of the eye. |
| salpingo-oophorectomy |
Excision of an ovary and a fallopian tube. |
| Sjogren’s syndrome |
A chronic, slowly progressive autoimmune disorder characterized by dryness of the eyes and mouth and recurrent salivary gland enlargement. This is called the sicca complex and is diagnostic. |
| spastic paraparesis |
Paralysis usually involving groups of muscles; characterized by excessive tone and spasticity of muscles, exaggeration of tendon reflexes, positive Babinski’s reflex, no atrophy or wasting, except from prolonged disuse, and absence of reaction of degenerat |
| spondolytic polyradiculopathy† |
Inflammation of one or more vertebrae with diffuse root involvement. |
| sporadic |
Occurring occasionally or in scattered instances, as a disease. |
| sural |
Relating to the calf of the leg. |
| Sydenham’s chorea |
A disease of childhood usually associated with rheumatic fever and marked by involuntary purposeless contractions of the muscles of the trunk and extremities; anxiety; and impairment of memory and sometimes speech. |
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T |
| tardive dyskinesia |
A condition of slow, rhythmical, automatic stereotyped movements, either generalized or in single muscle groups. These occur as an undesired effect of therapy with certain psychotropic drugs, esp. the phenothiazines. |
| tau |
A protein that associates with microtubules and other elements of the cytoskeleton; accelerates tubulin polymerization and stabilizes microtubules. |
| trinucleotide repeat |
Three nucleotides, such as CAG, CTG or GAA, are tandemly repeated an abnormal number of times within a gene. The genetic transmission of trinucleotide repeat expansion disorders within families may show a pattern of increasing severity and earlier age of o |
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V |
| vagus |
The pneumogastric or 10th cranial nerve. It is a mixed nerve, having motor and sensory functions and a wider distribution than any of the other cranial nerves. |
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W |
| Wilson’s disease |
A hereditary syndrome transmitted as an autosomal recessive trait in which a decrease of ceruloplasmin permits accumulation of copper in various organs (brain, liver, kidney, and cornea) associated with increased intestinal absorption of copper. |
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X |
| X-linked recessive |
Individuals possessing one copy of a mutation on the X chromosome will be affected. |
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