Androgen receptor CAG and GGN polymorphisms in boys with isolated hypospadias

New frontiers on the molecular underpinnings of hypospadias according to severity

Hypospadias, which is characterised by the displacement of the urethral meatus from its typical anatomical location in males, shows various degrees of severity. In this systematic review, we surveyed our current understanding of the genetics of isolated hypospadias in humans according to the severity of the condition. We found that sequencing and genotyping approaches were the preferred methods of study and that single nucleotide polymorphisms were the most common finding associated with hypospadias. Most genes fell into four gene-pathway categories related to androgens, oestrogens, growth factors, or transcription factors. Few hypospadias studies classify their findings by severity. Taken together, we argue that it is advantageous to take into consideration the severity of the condition in search of novel candidates in the aetiology of hypospadias. Abbreviations: AR: androgen receptor; ATF3: activating transcription factor 3; BMP4: bone morphogenetic protein 4; BMP7: bone morphogenetic protein 7; CYP17: steroid 17-alpha-hydroxylase/17,20 lyase; CYP1A1: cytochrome P450 1A1; CYP3A4: cytochrome P450 3A4; CNVs: copy number variants; DGKK: diacylglycerol kinase kappa; ESR1: oestrogen receptor 1; ESR2: oestrogen receptor 2; FGF8: fibroblast growth factor 8; FGF10: fibroblast growth factor 10; FGFR2: fibroblast growth factor receptor 2; HOXA4: homeobox protein Hox-A4; HOXB6: homeobox protein Hox-B6; HSD17B3: hydroxysteroid 17-beta dehydrogenase 3; MAMLD1: mastermind-like domain-containing protein 1; SF-1: splicing factor 1; SHH: sonic hedgehog; SNPs: single nucleotide polymorphisms; SOX9: SRY-box 9; SRD5A2: steroid 5 alpha-reductase 2; SRY: sex-determining region Y protein; STAR: steroidogenic acute regulatory protein; STARD3: StAR-related lipid transfer protein 3; STS: steryl-sulfatase; WT1: Wilms tumour protein; ZEB1: zinc finger oestrogen-box binding homeobox 1.

Role of PERK-eIF2α signaling pathway in fetal male rats with hypospadias induced by di-n-butyl phthalate

This study aims to explore the role of PERK-eIF2α signaling pathway in fetal male rats with hypospadias induced by maternal exposure to di-n-butyl phthalate (DBP). DBP was used to treat pregnant SD rats by gastric intubation from gestation day (GD) 14-18 to construct a hypospadias rat model. The amount, weight, anogenital distance (AGD), and hypospadias incidence of rats were recorded and the genital tubercle (GT) of fetal male rats was collected on GD 19. Western blotting was performed to detect the expressions of PERK-eIF2α pathway- and autophagy-related proteins, and cell apoptosis was detected using TUNEL method. Then, GT fibroblasts of fetal rats were obtained and transfected with PERK-siRNA to detect cell apoptosis and autophagy in each transfected group. The incidence of hypospadias was 43.49% in fetal male rats induced by DBP. The fetal rats in DBP group presented the decreased birth weight and anogenital distance (AGD)/body weight ratio than the Control group (all P < 0.05). Further, p-PERK, p-eIF2α and ATF4 protein expressions and the ratio of LC3-II/LC3-I were greatly increased in the GTs of fetal rats, while apoptosis index (AI) and P62 protein expression were evidently decreased (all P < 0.05). In addition, the apoptosis rate was increased in GT fibroblasts after transfection of PERK-siRNA with the increased P62 and reduced LC3-II/LC3-I ratio (all P < 0.05). Activation of PERK-eIF2α signaling pathway can influence the GT development of fetal male rats with hypospadias induced by DBP through activation of autophagy and inhibition of apoptosis.

No effect of AR polyG polymorphism on spinal and bulbar muscular atrophy phenotype

BACKGROUND AND PURPOSE

Disease severity varies considerably among patients with Spinal and Bulbar Muscular Atrophy (SBMA). Our aim was to investigate the role of androgen receptor (AR) polymorphic repeats in SBMA phenotype.

METHODS

We analyzed the length of AR polyQ and polyG tracts in 159 SBMA patients.

RESULTS

No relationship between polyG size or polyG/polyQ haplotypes and clinical phenotype was found. An independent negative correlation between polyQ-length and onset of weakness was confirmed (P < 0.001).

CONCLUSIONS

The negative results of our study prompt to continue the search for potential disease modifiers in SBMA outside the AR gene.

Non-linear association between androgen receptor CAG and GGN repeat lengths and reproductive parameters in fertile European and Inuit men

Recently the dogma that there is an inverse linear association between androgen receptor (AR) CAG and GGN polymorphisms and receptor activity has been challenged. We analysed the pattern of association between 21 male reproductive phenotypes and AR CAG/GGN repeat lengths in 557 proven-fertile men. A linear association was only found between sperm DNA fragmentation index (DFI) and CAG length, and between inhibin B and GGN length. Men with longer CAG then the reference (22-24), had higher oestradiol levels, whereas men with shorter CAG stretches had a higher DFI and a higher proportion of Fas-positive germ cells. Subjects with either short or long CAG had increased seminal levels of prostate-specific antigen and neutral α-glucosidase activity. Compared to men with the median GGN length of 23, those with shorter GGN repeats had higher levels of inhibin B, higher proportions of normal and progressive sperm, and a higher fraction of Fas-positive sperm, while men with longer GGN had higher oestradiol levels. These data indicate that at least for some markers of male reproductive function the association with CAG or GGN repeat length is curvilinear.