| Huntington | George, U.S. Physician, 1850-1916. See: Huntington's chorea, Huntington's disease. (05 Mar 2000) |
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| Huntington chorea | <neurology> An inherited adult-onset disease of the central nervous system. It is characterised by dementia and bizarre involuntary movements. The disease is progressive and there is currently no known cure. The identification of the gene (huntingtin) on chromosome 4p now allows for direct mutation analysis. The gene contains a trinucleotide repeat (CAG) that is found to be expanded in length in affected patients. The normal allele size ranges from 11 to 34 triplet repeat units, while 42 repeats or greater is considered diagnostic of Huntington disease. As in other trinucleotide repeat disorders, the phenomenom of anticipation has been observed, in this case expressed as earlier age of onset in offspring, particularly with paternal transmission. A further complication is the presence of two neighboring trinucleotide repeats (both CCG) which can expand independently without causing the disease. Early PCR primer sets encompassed these adjacent repeats, potentially yielding false positive test results, newer primers hone in more closely on the CAG repeat sequence. Careful attention must be paid to the psychosocial support structure of prospective test subjects in Huntington disease genetic counseling. Established protocols require systematic neuropsychiatric assessment and informed consent prior to DNA testing. Inheritance: autosomal dominant. (29 Dec 1997) |
| Huntington disease | <neurology> An inherited adult-onset disease of the central nervous system. It is characterised by dementia and bizarre involuntary movements. The disease is progressive and there is currently no known cure. The identification of the gene (huntingtin) on chromosome 4p now allows for direct mutation analysis. The gene contains a trinucleotide repeat (CAG) that is found to be expanded in length in affected patients. The normal allele size ranges from 11 to 34 triplet repeat units, while 42 repeats or greater is considered diagnostic of Huntington disease. As in other trinucleotide repeat disorders, the phenomenom of anticipation has been observed, in this case expressed as earlier age of onset in offspring, particularly with paternal transmission. A further complication is the presence of two neighboring trinucleotide repeats (both CCG) which can expand independently without causing the disease. Early PCR primer sets encompassed these adjacent repeats, potentially yielding false positive test results, newer primers hone in more closely on the CAG repeat sequence. Careful attention must be paid to the psychosocial support structure of prospective test subjects in Huntington disease genetic counseling. Established protocols require systematic neuropsychiatric assessment and informed consent prior to DNA testing. Inheritance: autosomal dominant. (29 Dec 1997) |
| Huntington's chorea | A progressive disorder usually beginning in young to middle age, consisting of a triad of choreoathetosis, dementia, and autosomal dominant inheritance with complete penetrance. Bilateral marked wasting of the putamen and the head of the caudate nucleus is characteristic. Synonym: chronic progressive chorea, degenerative chorea, hereditary chorea, Huntington's disease. (05 Mar 2000) |
| huntington's disease | An hereditary disorder with mental and physical deterioration leading to death. Although characterised as an adult-onset disease (as is usually the case), we have seen children with full-blown huntington's disease. (12 Dec 1998) |
| disease, huntington's | An hereditary disorder with mental and physical deterioration leading to death. Although characterised as an adult-onset disease (as is usually the case), we have seen children with full-blown Huntington's disease. (12 Dec 1998) |
| arrayed library | <molecular biology> Individual primary recombinant clones (hosted in phage, cosmid, YAC, or other vector) that are placed in two-dimensional arrays in microtiter dishes. Each primary clone can be identified by the identity of the plate and the clone location (row and column) on that plate. Arrayed libraries of clones can be used for many applications, including screening for a specific gene or genomic region of interest as well as for physical mapping. Information gathered on individual clones from various genetic linkage and physical map analyses is entered into a relational database and used to construct physical and genetic linkage maps simultaneously, clone identifiers serve to interrelate the multilevel maps. Compare: library, genomic library. (19 Jan 1998) |
| gene library | <molecular biology> A collection of cloned DNA fragments that contains all the genetic information of a particular organism. (09 Oct 1997) |
| genomic library | <molecular biology> A collection of DNA molecules, derived from restriction fragments that have been cloned in vectors, that includes all or part of the genetic material of an organism. (18 Nov 1997) |
| cDNA library | <molecular biology> A collection of all of the mRNA molecules present in a cell or organism, all turned into cDNA molecules with the enzyme reverse transcriptase, then inserted into vectors (other DNA molecules which can continue to replicate after addition of foreign DNA). The library can then be probed for the specific cDNA (and thus mRNA) of interest. (09 Oct 1997) |
| peptide library | A collection of cloned free peptides, frequently consisting of all possible combinations of amino acids making up an n-amino acid peptide. (12 Dec 1998) |
| complementary DNA library | <molecular biology> A collection of all of the mRNA molecules present in a cell or organism, all turned into cDNA molecules with the enzyme reverse transcriptase, then inserted into vectors (other DNA molecules which can continue to replicate after addition of foreign DNA). The library can then be probed for the specific cDNA (and thus mRNA) of interest. (09 Oct 1997) |
| national library of medicine | An agency of the national institutes of health concerned with overall planning, promoting, and administering programs pertaining to various aspects of documentation and library services in the field of medicine. (12 Dec 1998) |
| DNA library | <molecular biology> A collection of DNA molecules, derived from restriction fragments that have been cloned in vectors, that includes all or part of the genetic material of an organism. (18 Nov 1997) |
| epitope library | <molecular biology> Large collection (hundreds of millions) of peptides each encoded by a randomly mutated piece of DNA in a phage genome and expressed on the surface of that bacteriophage, sometimes as an N terminal extension of a coat protein. Particular phages can be selected by a binding assay and since the peptide has its encoding DNA associated with it sequencing is straightforward. (18 Nov 1997) |