Polyglutamine (Poly Q) diseases are a group of neurodegenerative disorders, caused by the formation of PolyQ mutants due to trinucleotide repeats expansion in coding regions of disease-causing genes, which eventually lead to selective neuronal degeneration and death with unclarified pathogenesis. As a new type of genetic regulatory factor, microRNA (miRNA) plays an important role in modulating gene expression in eukaryote. During the recent years, more attention was paid to roles and related mechanism of miRNA involving in neurodegenerative disease, especially PolyQ diseases. This review is focused on research progress in roles of miRNA in the pathogenesis of PolyQ diseases.
Eukaryota ; MicroRNAs ; genetics ; physiology ; Nerve Degeneration ; Neurodegenerative Diseases ; genetics ; Peptides ; genetics ; Trinucleotide Repeat Expansion ; genetics ; Trinucleotide Repeats ; genetics

A total of 12 775 SSRs were identified from Scutellaria baicalensis Georgi genomic database, accounting for 2.56% of the total genomic sequences. The result showed that S. baicalensis SSRs were based on 68.32% dinucleotide and 18.63% trinucleotide repeats; CT/GA and TTC/GAA were predominant in the dinucleotide motifs and the trinucleotide motifs respectively. Nine primers were selected to produce highly reproducible SSR bands and were used in studying the genetic diversity of S. baicalensis, 50 individuals from ten populations. 68 SSR polymorphic loci were detected, these loci were polymorphic and displayed 4 to 12 alleles per locus with a mean number of 7; the effect number of alleles was 3. Expected heterozygosities were 0.6 and were far more greater than the average in dicotyledonous plants. PIC (polymorphism information content) was 0.72, Shannon's information index was 1.32, these all proved that S. baicalensis had a high genetic diversity in general. Genetic differentiation among population Gst was 0.131, genetic variation among population accounted for 13.1% and genetic variation within population accounted for 86.9%. The cluster analysis showed that 10 populations S. Baicalensis were classified into 2 groups, but it was not associated with geographical distribution.
Alleles ; Cluster Analysis ; Genetic Variation ; Genomics ; Microsatellite Repeats ; Scutellaria baicalensis ; genetics ; Trinucleotide Repeats

Polyglutamine(PolyQ) diseases comprise a group of inherited neurodegenerative disorders with significant clinical and genetic heterogeneity. Although they share a common mechanism involving dynamic expansion of CAG trinucleotide repeats, their clinical features may vary and there has been no specific treatment. Recently, much attention had been attracted to microRNAs which, as a new type of posttranscription regulatory factor, have proven to significantly affect the progress of PolyQ disease. This review will focus on the roles of microRNAs in the pathogenesis of PolyQ diseases and their potential use for therapy.
Humans ; MicroRNAs ; genetics ; Neurodegenerative Diseases ; genetics ; Peptides ; genetics ; Trinucleotide Repeats ; genetics

OBJECTIVETo explore the association of the androgenic receptor (AR) CAG repeats with the risks of benign prostatic hyperplasia (BPH) and prostate cancer (PCa).

METHODSWe searched the major databases at home and abroad for the literature addressing the correlation of the AR gene CAG repeats with BPH and PCa. Based on the results of heterogeneity tests, we used the M-H fixed effect model and random effect model to pool the odds ratio (OR) effect size. We evaluated publication bias by Begg and Egger bias analysis, investigated the association of CAG repeats with the risks of BPH and PCa by systematic review, and stratified their relationship according to the races of the patients.

RESULTSBased on the selection criteria, 4 of the 29 identified studies were included, with 485 cases of BPH, 767 cases of PCa, and 709 controls. There was no heterogeneity between the BPH and control groups, and no correlation between short CAG repeats and BPH after pooling the odds ratio (OR) effect size. Heterogeneity was found among the BPH, PCa and control groups. Random effects model suggested an association of short CAG repeats with the risk of PCa (OR(PCa/control) = 1.45, OR(PCa/BPH) = 1.86, OR(PCa/(BPH + control)) = 1.66), while subgroup analysis with racial stratification indicated inter-ethnic differences between the two. Begg and Egger bias analysis showed no significant publication bias.

CONCLUSIONShorter CAG repeats are positively correlated with the risk of PCa but not with that of BPH.

Humans ; Male ; Polymorphism, Genetic ; Prostatic Hyperplasia ; genetics ; Prostatic Neoplasms ; genetics ; Receptors, Androgen ; genetics ; Trinucleotide Repeats

Ataxins ; Humans ; Male ; Middle Aged ; Nerve Tissue Proteins ; genetics ; Spinocerebellar Ataxias ; genetics ; Trinucleotide Repeats

OBJECTIVETo assess the association of male infertility with CAG repeat polymorphism of the androgen receptor (AR) gene by meta-analysis.

METHODSWe identified the case-control studies on the relationship of male infertility with CAG repeats of the AR gene by searching Medline/PubMed and CBM databases, and conducted meta-analysis on the data obtained with the RevMan 4.2 software.

RESULTSThirty-two eligible articles were selected in this study, including 3,153 idiopathic infertile men and 2,314 controls. The combined data statistics showed that all the infertile men had a significantly higher mean of CAG repeats than the controls (SMD = 0.27, 95% CI: 0.17-0.37, P < 0.01). The specific SMD between the infertile patients and controls was 0.29, 95% CI: 0.08-0.50 for the azoospermic men, 0.27, 95% CI: 0.13-0.41 for the moderate oligozoospermic men, and 0.18, 95% CI: 0.02-0.33 for the severe oligozoospermic cases. The results of sensitivity analyses were consistent with those mentioned above.

CONCLUSIONThe increased length of CAG repeats in the AR gene may be correlated with the risk of the impairment of spermatogenesis.

Humans ; Infertility, Male ; etiology ; genetics ; Male ; Polymorphism, Genetic ; Receptors, Androgen ; genetics ; Trinucleotide Repeats

I previously reported the PCR-based Spinal and bulbar muscular atrophy (SBMA) region polymorphisms in the three northeast Asian populations (Chinese, Koreans, Japanese) and Caucasians. Here I update this analysis by including the data of the allele distribution in 378 unrelated individuals from four populations in Asia. In this study I investigated PCR-based CAG repeat polymorphism on the SBMA locus among four Asian populations (Mongolian, Evenki, Orochon, Negrito) and performed the statistical analysis on the eight populations including the previously analyzed data. Both statistical analyses of one-way ANOVA (F=3.284, P=0.002) and Kruskal-Wallis test (chi-square=21.542, DF=7, P=0.003) showed remarkable differences in CAG allele distributions among the populations. Post-hoc test showed that the difference between Negritos and Caucasians was especially significant (Scheffe: P=0.042; Bonferroni: P=0.004). Also a significant differences among Northeast Asians, Caucasians and Negritos (Southeast Asian) were detected by these two tests (ANOVA; F=8.132, P.0.000, Kruskal-Wallis; chi-square=16.614, DF=2, P.0.000). Post-hoc test showed that the differences between Negritos and Caucasias was also especially significant (Scheffe: P=0.001; Bonferroni: P=0.000) among these three groups. These data present that the CAG repeat polymorphism of SBMA gene has a useful information for studies of human population genetics.
Alleles ; Asia ; Asian Continental Ancestry Group* ; Genetics, Population ; Humans ; Muscular Disorders, Atrophic* ; Trinucleotide Repeats*

OBJECTIVETo observe trinucleotide repeat number, (CTG)n in the 3'-untranslated region of the myotonic protein kinase (MTPK) gene in a clinically suspected woman with myotonic dystrophy (DM) family history and her abortus, in order to confirm the necessity of exerting antenatal examination in patients or suspected individuals with DM family history.

METHODSLong Expand Template polymerase chain reaction (PCR) system was used to analyze CTG trinucleotide repeat numbers located in the 3' untranslated region of MTPK on chromosome 19q13.2-3 in both peripheral white cells and muscles of the suspected mother and the other two DM patients in the family. The tissues of her abortus and blood of a health woman were detected, too.

RESULTSCTG repeats in both peripheral white cells and muscles of the suspected mother and the tissue of abortus were higher than normal range of CTG repeat number. There is no significant difference between blood and muscle samples. High CTG repeats were detected in blood and muscles of the typical DM members in the family, but in the blood sample of control, CTG repeats is normal.

CONCLUSIONCTG trinucleotide analyses and antenatal examination should be done in pregnant with a DM family history, in order to reduce the birth rate of DM offspring.

Adult ; DNA ; analysis ; Female ; Fetus ; metabolism ; Humans ; Myotonic Dystrophy ; diagnosis ; genetics ; Prenatal Diagnosis ; Trinucleotide Repeats

Simple and effective methods are needed for the identification of Chinese medicinal material species and their variety. Lonicera japonica Thunb. is one of Chinese herbal medicines widely demanded. A total of 3 705 EST-SSRs of L. japonica and 2 818 EST-SSRs of L. japonica var. chinensis Thunb. were identified from EST database in our lab. In average, there was one EST-SSR per 4.05 kb in L. japonica ESTs and per 7.49 kb in L. japonica var. chinensis ESTs, separately. The identified SSRs in L. japonica were consisted of 51.98% dinucleotide and 34.61% trinucleotide repeats, while SSRs in L. japonica var. chinensis had 57.45% dinucleotide and 30.09% trinucleotide. The results reviewed that the classes AG/TC and GAG/TCT were predominant in the dinucleotide motifs and the trinucleotide motifs, respectively. Total 87 EST-SSRs were identified of significant difference between L. japonica and L. japonica var. chinensis. PCR products were obtained from 52 L. japonica samples in 13 out of 15 SSR markers tested. The polymorphism in L. japonica, L. japonica var. chinensis and other honeysuckles could be distinguished by three markers (jp.ssr4, jp.ssr64 and jp.ssr65) tested.
Dinucleotide Repeats ; Expressed Sequence Tags ; Flowers ; genetics ; Lonicera ; classification ; genetics ; Microsatellite Repeats ; Plants, Medicinal ; classification ; genetics ; Polymerase Chain Reaction ; Polymorphism, Genetic ; Trinucleotide Repeats

OBJECTIVE: To analyze the dynamic variant and clinical subtype of a pedigree affected with spinocerebellar ataxia (SCA) by using fluorescent-labeled primer combined with capillary electrophoresis. METHODS: Genomic DNA was extracted from 8 members including 6 patients and 2 healthy individuals from the pedigree. Six pairs of fluorescent-labeled primers were designed to screen pathological variants in association with common subtypes of SCA including SCA1, SCA2, SCA3, SCA6, SCA12 and SCA17.The PCR products were detected by capillary electrophoresis. RESULTS: The number of CAG repeats in the SCA3 gene of the proband were determined as 8 and 70, exceeded the normal range(12 to 40), which suggested a diagnosis of SCA3. The other five patients were all detected with abnormal CAG repeats in the SCA3 gene, while the two healthy individuals were determined to be within the normal range. CONCLUSION The abnormal expansion of CAG repeats in the SCA3 gene probably underlay the pathogenesis of the disease in this pedigree. Combined fluorescent-labeled primers PCR and capillary electrophoresis can detect dynamic variants among SCA patients with efficiency and accuracy.
Ataxin-3/genetics* ; Genetic Variation ; Humans ; Machado-Joseph Disease/genetics* ; Pedigree ; Repressor Proteins/genetics* ; Trinucleotide Repeats/genetics*