title: Androgen receptor gene polyglutamine length is associated with testicular histology in infertile patients.
abstract: OBJECTIVE
  Androgens and a functioning androgen receptor are required for normal spermatogenesis. The androgen receptor gene (AR) has a repetitive DNA sequence in exon 1 that encodes a polyglutamine tract. Within the normal polymorphic range this (CAG)(n) tract length is inversely related to the transcriptional activity of the androgen receptor. In a prospective analysis we determined the association of AR (CAG)(n) tract length with testicular histology in infertile males.
  
  
  METHODS
  Blood DNA from 70 severely infertile patients without obstruction who were undergoing testicular biopsy was amplified by polymerase chain reaction targeting the AR (CAG)(n) tract. A total of 37, 15 and 18 men presented with the Sertoli-cell-only syndrome, maturation arrest and hypospermatogenesis, respectively. Blood DNA from 55 fertile men served as the control. Polymerase chain reaction amplified DNA was direct sequenced using a genetic analyzer.
  
  
  RESULTS
  Median CAG repeat length was 22 (range 17 to 33) in infertile patients and 21 (range 8 to 27) in controls (p = 0.009), including 22 (range 17 to 30) in patients with the Sertoli-cell-only syndrome, 22 (range 18 to 28) in those with maturation arrest and 23 (19 to 33) in those with hypospermatogenesis. Statistical significance was noted for the hypospermatogenesis versus control groups (p = 0.039) but not for the groups with the Sertoli-cell-only syndrome or maturation arrest versus the control group (p = 0.054 and 0.591, respectively).
  
  
  CONCLUSIONS
  Infertile males with testicular failure, particularly those with hypospermatogenesis, are more likely to have a longer androgen receptor polyglutamine tract than controls. Polymorphisms of the AR (CAG)(n) tract may contribute to spermatogenesis efficiency through a subtle modulatory effect on androgen receptor function.
authors.affiliation: Scott Department of Urology, Baylor College of Medicine, Houston, TX, USA.
authors.forename: Roberto
authors.initials: R
authors.lastname: Casella
authors.forename: Maria R
authors.initials: MR
authors.lastname: Maduro
authors.forename: Amparo
authors.initials: A
authors.lastname: Misfud
authors.forename: Larry I
authors.initials: LI
authors.lastname: Lipshultz
authors.forename: Eu Leong
authors.initials: EL
authors.lastname: Yong
authors.forename: Dolores J
authors.initials: DJ
authors.lastname: Lamb
mesh_terms: D000328:Adult; D000368:Aged; D005973:Glutamine / Q000235:genetics*; D006801:Humans; D007248:Infertility, Male / Q000235:genetics* / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D010455:Peptides / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011944:Receptors, Androgen / Q000235:genetics*; D020449:Repetitive Sequences, Amino Acid; D012708:Sertoli Cells / Q000473:pathology; D013076:Sperm Count; D013737:Testis / Q000473:pathology*; D018911:Trinucleotide Repeats
chemical_list: D010455:Peptides; D011944:Receptors, Androgen; D005973:Glutamine; C097188:polyglutamine