Expansions of trinucleotide repeats in DNA, a novel source of mutations associated with human disease, may arise by DNA replication slippage initiated by hairpin folding of primer or template strands containing such repeats. To evaluate the stability of single-strand folding by repeating triplets of DNA bases, thermal melting profiles of (CAG)10, (CTG)10, (GAC)10 and (GTC)10 strands are determi...

Two studies used a sample of 300 female Australian monozygotic twins who had been genotyped for the X-linked androgen receptor gene and scored for the number of repeats of the triplet CAG. (A low number of repeats is associated with greater risk of prostate cancer in males and more e€ective transcription of androgens). In the ®rst study, three measures of masculinity±femininity were constructed...

OBJECTIVE To analyze the ataxin 2 (ATXN2) CAG repeat size in a cohort of patients with amyotrophic lateral sclerosis (ALS) and healthy controls. Large (CAG)(n) alleles of the ATXN2 gene (27-33 repeats) were recently reported to be associated with an increased risk of ALS. DESIGN Case-control study. SETTING France and Quebec, Canada. PARTICIPANTS A total of 556 case patients with ALS and 4...

Trinucleotide repeats are involved in several neurological disorders in humans. DNA sequences containing CAG/CTG repeats are prone to slippage during replication and double-strand break repair. The effects of trinucleotide repeats on transcription and on nuclear export were analyzed in vivo in yeast. Transcription of a CAG/CTG trinucleotide repeat in the 3'-untranslated region of a URA3 reporte...

Chromosome abnormalities, Y-chromosome microdeletions, and androgen receptor gene CAG and GGN repeat polymorphisms in infertile Chinese men featuring severe oligospermia and azoospermia were analyzed. Ninety-six fertile men and 189 non-obstructive infertile men, including 125 patients with azoospermia and 64 with severe oligozoospermia, were studied. Seventeen infertile men (9.0%) carried a chr...

The R6/2 mouse is the most frequently used model for experimental and preclinical drug trials in Huntington's disease (HD). When the R6/2 mouse was first developed, it carried exon 1 of the huntingtin gene with ~150 cytosine-adenine-guanine (CAG) repeats. The model presented with a rapid and aggressive phenotype that shared many features with the human condition and was particularly similar to ...

OBJECTIVE To explore the profile of cytosine/adenine/guanine (CAG) repeat expansion in Omani spinocerebellar ataxia (SCA) patients. METHODS Ten SCA patients attending the Sultan Qaboos University Hospital Neurologic clinics, Al-Khoud, Oman in the 3 years starting from January 2000 were recruited for this study. Genomic DNA was extracted from peripheral blood samples and CAG repeat expansion a...

Huntington's disease (HD) is a neurodegenerative disorder characterized by a triad of choreoathetosis, dementia and dominant inheritance. The cause of HD is an expansion of CAG trinucleotide repeats in the HD gene. Typical age at onset of symptoms is in the 40s, but the disorder can manifest at any time. Late-onset (≥ 60 years) HD is clinically different from other adult or juvenile onset HD an...

Human androgen receptor (AR) contains a highly polymorphic polyglutamine tract encoded by CAG repeats [(CAG)n] in exon 1 of the AR gene. The CAG repeats, ranging from 11 to 38, have been reported to be inversely correlated with AR activity. A case-control study involving 261 polycystic ovary syndrome (PCOS) patients and 278 healthy controls was conducted. Fluorescently labeled DNA fragments con...

In this issue, Chen et al. (1) report results from a nested case-control study that examines a CAG repeat region in exon 1 of the androgen receptor gene (AR) in relation to risk of prostate cancer. In contrast with most of the early reports (2–4), but consistent with several more recent reports (5–9), fewer AR CAG repeats were not associated with higher risk of prostate cancer. The study by Che...