Androgen insensitivity syndrome: do trinucleotide repeats in androgen receptor gene have any role?
OBJECTIVE
To investigate the role of CAG and GGN repeats as genetic background affecting androgen insensitivity syndrome (AIS) phenotype.


METHODS
We analyzed lengths of androgen receptor (AR)-CAG and GGN repeats in 69 AIS cases, along with 136 unrelated normal male individuals. The lengths of repeats were analyzed using polymerase chain reaction (PCR) amplification followed by allelic genotyping to determine allele length.


RESULTS
Our study revealed significantly shorter mean lengths of CAG repeats in patients (mean 18.25 repeats, range 14-26 repeats) in comparison to the controls (mean 22.57 repeats, range 12-39 repeats) (two-tailed P < 0.0001). GGN repeats, however, did not differ significantly between patients (mean 21.48 repeats) and controls (mean 21.21 repeats) (two-tailed P = 0.474). Among patients' groups, the mean number of CAG repeats in partial androgen insensitivity cases (mean 15.83 repeats) was significantly less than in complete androgen insensitivity cases (mean 19.46 repeats) (two-tailed P < 0.0001).


CONCLUSIONS
The findings suggest that shorter lengths of repeats in the AR gene might act as low penetrance genetic background in varying manifestation of androgen insensitivity.
Rajender
Singh
S
Centre for Cellular and Molecular Biology, Hyderabad, India.
Gupta
Nalini J
NJ
Chakravarty
Baidyanath
B
Singh
Lalji
L
Thangaraj
Kumarasamy
K
D013734:Androgen-Insensitivity Syndrome / Q000235:genetics*; D004247:DNA / Q000235:genetics; D005640:Follicle Stimulating Hormone / Q000097:blood; D020022:Genetic Predisposition to Disease; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D010641:Phenotype; D011944:Receptors, Androgen / Q000235:genetics*; D012044:Regression Analysis; D013739:Testosterone / Q000097:blood; D018911:Trinucleotide Repeats / Q000235:genetics*
D011944:Receptors, Androgen; D013739:Testosterone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D004247:DNA