More than fifteen genetic diseases, including Huntington's disease, myotonic dystrophy 1, fragile X syndrome and Friedreich ataxia, are caused by the aberrant expansion of a trinucleotide repeat. The mutation is unstable and further expands in specific cells or tissues with time, which can accelerate disease progression. DNA damage and base excision repair (BER) are involved in repeat instabili...

Single-molecule DNA analysis of testicular germ cells isolated by laser capture microdissection from two Huntington disease patients showed that trinucleotide repeat expansion mutations were present before the end of the first meiotic division, and some mutations were present even before meiosis began. Most of the larger Huntington disease mutations were found in the postmeiotic cell population...

Trinucleotide repeat (TNR) expansions are present in a wide range of genes involved in several neurological disorders, being directly involved in the molecular mechanisms underlying pathogenesis through modulation of gene expression and/or the function of the RNA or protein it encodes. Structural and functional information on the role of TNR sequences in RNA and protein is crucial to understand...

| The underlying genetic mutations for many inherited neurodegenerative disorders have been identified in recent years. One frequent type of mutation is trinucleotide repeat expansion. Depending on the location of the repeat expansion, the mutation might result in a loss of function of the disease gene, a toxic gain of function or both. Disease gene identification has led to the development of ...

Dynamic mutations involve expansion of the number of repeat units consisting of three or more nucleotides in tandem (i.e. adjacent to one another) present in a gene or in its neighborhood. These repeats may occur in different genes and may code for different aminoacids. According to expansions sizes, it is possible to have unaffected individuals that are carriers of a pre-mutation. Instability ...

We observed an apparent series of insertions and deletions beginning 5 bp downstream of an A-->G silent transition in exon 1 of the tumor necrosis factor receptor 1 gene. The apparent sequence anomaly was observed only in individuals carrying the transition. Formamide gel electrophoresis revealed that the apparent sequence anomaly was due to compression. The compression is plausibly explained b...