Polymorphic (CAG)n repeats in the androgen receptor gene

Noor Ahmad Shaik, Govindan S, Sujatha Govindan, Vijayalakshmi Kodati, Kodati V, Kaipa Prabhakar Rao, K. Prabhakar Rao, Rao KP, Qurratulain Hasan, Hasan Q
Hematology/oncology and stem cell therapy · 2009 · vol. 2(1) , pp. 289–293 · doi:10.1016/s1658-3876(09)50040-4 · PMID:20063560 · W2004134992
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This study analyzed androgen receptor gene (CAG)n repeat lengths in Asian Indian women, finding that 19 and 20 repeats are associated with higher risk for endometriosis and leiomyomas, respectively.

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This study investigated whether polymorphic (CAG)n repeats in the androgen receptor gene serve as risk markers for endometriosis and uterine leiomyomas within an Asian Indian population. Researchers analyzed DNA from 331 participants, including patients with endometriosis or leiomyomas and healthy controls, using PCR amplification and sequencing to determine repeat lengths. The results indicated a statistically significant association between specific repeat counts and disease status, identifying nineteen CAG repeats as elevated in endometriosis cases and twenty repeats as elevated in leiomyoma cases compared to controls. This paper is centrally about endometriosis — specifically evaluating the AR gene (CAG)n repeat polymorphism as a genetic risk marker for the condition alongside uterine leiomyomas.

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Abstract

BACKGROUND: Endometriosis and uterine leiomyomas are leading hormone responsive, benign uterine disorders responsible for high morbidity in women of reproductive age group. A polymorphic (CAG)n repeat length located in exon 1 of the androgen receptor (AR) gene has been proposed as a risk marker for both endometriosis and leiomyomas in some ethnic groups. The present study was carried out to assess the frequency of AR (CAG)n repeat polymorphism as a risk marker for endometriosis and uterine leiomyomas in Asian Indian women. METHODS: DNA was isolated from peripheral blood samples of 331 subjects, which include 90 endometriosis cases, 140 cases of leiomyomas and 101 healthy age- and sex-matched controls. PCR was carried out to amplify exon 1 of the AR gene. All the PCR amplicons were analysed initially on 2% agarose gel electrophoresis, followed by bidirectional sequencing to calculate the number CAG repeats in individuals. RESULTS: The CAG repeat ranges detected in endometriosis cases were 4-33 (Mode-19) and in leiomyomas cases 5-34 (Mode-20), whereas in controls it was 5-34 (Mode-22). A distinct variation was observed in the three groups at 14, 18, 19, 20 and 22 (CAG)n repeats, which were statistically analyzed using chi-square and odds ratio tests. 19 CAG repeats were found to be higher in endometriosis cases (19.09%) when compared with controls (9.04%), while 20 CAG repeats were higher in leiomyomas cases (14.02%) compared to controls (6.14%). A statistically significant (P < 0.05) association was observed in 19 and 20 CAG repeats in endometriosis and leiomyomas, respectively. CONCLUSION: This is the first report from an Asian Indian population proposing that 19 and 20 CAG repeats of the AR gene are associated with endometriosis and leiomyoma and can be regarded as high-risk markers.
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Background

Endometriosis and uterine leiomyomas are leading hormone responsive, benign uterine disorders responsible for high morbidity in women of reproductive age group. A polymorphic (CAG)n repeat length located in exon 1 of the androgen receptor (AR) gene has been proposed as a risk marker for both endometriosis and leiomyomas in some ethnic groups. The present study was carried out to assess the frequency of AR (CAG)n repeat polymorphism as a risk marker for endometriosis and uterine leiomyomas in Asian Indian women.

Methods

DNA was isolated from peripheral blood samples of 331 subjects, which include 90 endometriosis cases, 140 cases of leiomyomas and 101 healthy age- and sex-matched controls. PCR was carried out to amplify exon 1 of the AR gene. All the PCR amplicons were analysed initially on 2% agarose gel electrophoresis, followed by bidirectional sequencing to calculate the number CAG repeats in individuals.

Results

The CAG repeat ranges detected in endometriosis cases were 4-33 (Mode-19) and in leiomyomas cases 5-34 (Mode-20), whereas in controls it was 5-34 (Mode-22). A distinct variation was observed in the three groups at 14, 18, 19, 20 and 22 (CAG)n repeats, which were statistically analyzed using chi-square and odds ratio tests. 19 CAG repeats were found to be higher in endometriosis cases (19.09%) when compared with controls (9.04%), while 20 CAG repeats were higher in leiomyomas cases (14.02%) compared to controls (6.14%). A statistically significant (p<0.05) association was observed in 19 and 20 CAG repeats in endometriosis and leiomyomas, respectively.

Conclusion

This is the first report from an Asian Indian population proposing that 19 and 20 CAG repeats of the AR gene are associated with endometriosis and leiomyoma and can be regarded as high-risk markers.

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Condition tags

endometriosis

MeSH descriptors

Endometriosis Genetic Predisposition to Disease Leiomyoma Receptors, Androgen Trinucleotide Repeat Expansion Uterine Neoplasms Endometriosis Female Humans Leiomyoma Polymerase Chain Reaction Receptors, Androgen Trinucleotide Repeat Expansion Uterine Neoplasms

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