["Hypospadias is a common male congenital urethral malformation, defined as the displacement of the urethral meatus ventrally from the tip of the glans penis. The importance of androgen receptor in male external genitalia development has been well recognized. Recently, the presence of active estrogen receptors (ER) in the developing male external genitalia has also been demonstrated. There are two isoforms of the human estrogen receptor, ESR1 and ESR2, which occur, with distinct tissue and cell patterns of expression. We hypothesized that modifications in these nuclear receptors' genes could lead to hypospadias.", 'We screened 60 boys with hypospadias for mutations in the coding regions of ESR1 and ESR2 genes, by denaturing high-performance liquid chromatography and automated sequence analysis. We also genotyped the CA repeat polymorphism in ESR2 and the TA repeat polymorphism in ESR1.', 'The CA repeat polymorphism in ESR2 is prolonged in hypospadias patients compared to controls (p < 0.05). Prolongation of this CA repeat polymorphism has previously been associated with lower levels of testosterone. Six patients presented the genetic variant 2681-4A > G (rs944050) in the heterozygous form in ESR2, which was a significantly higher frequency than in the control population (p < 0.05). One of these patients also presented a 266_267insC in exon 1 of ESR2, which is also a known single nucleotide polymorphism (SNP; rs3832949). In ESR1, no significant gene alteration was found to be associated with hypospadias.'] Are polymorphisms of estrogen receptor beta gene associated with hypospadias?