Association of a tagging single nucleotide polymorphism in the androgen receptor gene region with susceptibility to severe hypospadias in a Caucasian population.

Hypospadias is a congenital malformation and a milder form of 46,XY disorder of sexual development (DSD). In the present study, we investigated 13 haplotype tagging single nucleotide polymorphisms (SNPs) covering the steroid-5-alpha reductase (SRD5A2) and androgen receptor(AR) gene region, respectively, in a cohort consisting of 260 individuals with mild hypospadias and 77 with severe disease, in addition to 471 healthy male controls. The investigated genes are known to have an important role in the hormone-dependent stage of sexual development. Our study revealed one novel marker located in the AR gene region (rs5919436; g.67024320C>G) to be significantly associated with an increased risk of severe hypospadias (adjusted p value: 0.02; odds ratio: 2.98). In concordance with this finding, we detected an association of a haplotype tagged by the minor allele of rs5919436 (adjusted p value: 0.04). We further detected no association between the investigated disease and the haplotype tagging polymorphisms covering the SRD5A2 gene, which is of importance considering the conflicting results reported previously. In conclusion, our data implicate that the AR rs5919436 (g.67024320C>G) polymorphism may act as a novel genetic marker for increased susceptibility to severe hypospadias in Caucasians.

The p.G146A and p.P125P polymorphisms in the steroidogenic factor-1 (SF-1) gene do not affect the risk for hypospadias in Caucasians.

Hypospadias is a frequent congenital malformation in boys and is characterized by incomplete fusion of the urethral folds. The steroidogenic factor-1 (SF-1, NR5A1) gene plays a key role in hypothalamic-pituitary-steroidogenic organ development, and has previously been reported to be mutated in individuals with 46,XY disorder of sex development. Here, we investigated the role of SF-1 in hypospadias, a milder form of 46,XY disorder of sex development. We performed direct sequencing analysis of the SF-1 gene in 2 male Caucasian twins exhibiting very severe hypospadias, and in 95 Caucasian boys with mild and severe hypospadias. We further extended the analysis by investigating 332 mild and severe hypospadias cases and 422 male controls using TaqMan assays. Our sequencing revealed a novel heterozygous p.R313H (c.938G>A) missense mutation in each twin, and no mutations in the 95 Caucasian cases. Instead, a missense p.G146A (c.437G>C), and a silent known p.P125P (c.375C>T) polymorphism, respectively, was found in several of the latter cases. Further investigation of the 2 polymorphisms in the larger material of cases and controls showed no significant genotypic or allelic association. In conclusion, the SF-1 gene may not play a significant role in the development of hypospadias in Caucasians.