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Trinucleotide repeat expansion in neurological disease
Author(s) -
La Spada Albert R.,
Paulson Henry L.,
Fischbeck Kenneth H.
Publication year - 1994
Publication title -
annals of neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.764
H-Index - 296
eISSN - 1531-8249
pISSN - 0364-5134
DOI - 10.1002/ana.410360604
Subject(s) - trinucleotide repeat expansion , spinal and bulbar muscular atrophy , myotonic dystrophy , polyglutamine tract , spinocerebellar ataxia , huntington's disease , genetics , myotonia , ataxia , atrophy , fragile x syndrome , biology , anticipation (artificial intelligence) , disease , huntingtin , medicine , allele , pathology , neuroscience , gene , androgen receptor , prostate cancer , cancer , artificial intelligence , computer science
Expansion of trincleotide repeats is now recognized as a major cause of neurological disease. At least seven disorders result from trinucleotide repeat expansion: X‐linked spinal and bulbar muscular atrophy (SBMA), two fragile×syndromes of mental retardation (FRAXA and FRAXE), myotonic dystrophy, Huntington's disease, spinocerebellar ataxia type 1 (SCA1), and dentatorubral‐pallidoluysian atrophy (DRPLA). The expanded trinucleotide repeats are unstable, and the phenomenon of anticipation, i.e., worsening of disease phenotype over successive generations, correlates with increasing expansion size. In this review, we compare the clinical and molecular features of the trinucleotide repeat diseases, which may be classified into two types. Fragile×and myotonic dystrophy are multisystem disorders usually associated with large expansions of untranslated repeats, while the four neurodegenerative disorders, SBMA, Huntington's disease, SCA1, and DRPLA, are caused by smaller expansions of CAG repeats within the protein coding portion of the gene. CAG repeats encode polyglutamine tracts. Polyglutamine tract expansion thus appears to be a common mechanism of inherited neurodegenerative disease. Although polyglutamine tract lenghthening presumably has a toxic gain of function effect in the CAG trinucleotide repeat disorders, the basis of this neuronal toxicity remains unknown.