We report on mutation screening and CAG repeat length analysis of the andro
gen receptor (AR) gene in 21 patients with hypospadias. The urethral meatus
was located at the glandular region in six patients (glandular type), at t
he penile shaft in seven patients (penile type), and at the scrotal/perinea
l region in eight patients (scrotal/perineal type). Mutation screening was
performed for exons 1-8 and their flanking introns (except for the CAG and
GGC repeat regions at exon 1) by the heteroduplex detection method and show
ed no abnormal chromatograms, The CAG repeat length analysis was carried ou
t using 50 normal boys and 50 fertile males as controls, and demonstrated n
o statistically significant difference in the median of CAG repeat lengths
or in the frequency of long CAG repeats (greater than or equal to 26 or gre
ater than or equal to8) between the controls and the patients with the thre
e different types of hypospadias. The results suggest that AR gene abnormal
ities do not constitute a major factor in the development of hypospadias.