ATF3, an Estrogen Reponsive Gene, is Mutated and Overexpressed in the Urethral Plate of Patients with Hypospadias
Abstract Purpose ATF3, an estrogen-responsive gene expressed during genital development, is a strong candidate gene in the development of hypospadias. It is indeed the most upregulated gene in hypospadiac skin and it is implicated in cell cycling suppression that may interfere with urethral cell growth. We thus investigated the sequence and the expression of ATF3 in hypospadias. Material and Methods Direct sequencing of coding exons and splicing sites of ATF3 was performed in 41 boys with hypospadias and 30 controls. ATF3 expression in the genital tubercle of fetuses with and without hypospadias was also studied by immunochemistry. Results -A missense mutation (Leu23Met) was identified in a boy with anterior hypospadias. This aminoacid is highly conserved through species and may be of functional interest. -3 mutations (C53616T, C54177A, Ins54489A) were found in or close to exon 6. This important exon includes splicing sites for an alternative transcript (ATF3ΔZip) implicated in the regulation of the function of ATF3. The phenotypes associated with these mutations were perineal, penoscrotal and anterior hypospadias. None of these mutations were present in controls. -Immunochemistry revealed that ATF3, which is undetectable around the urethra in normal fetus, is overexpressed in the urethral plate and subcutaneous tissue of hypospadiac specimen, especially around the ectopic orifice of urethra. Conclusions This first report of ATF3 mutations in hypospadias, coupled with its particular expression pattern in hypospadiac fetus, highlight the role of ATF3 in this frequent malformation. These results further support the importance of estrogen responsive genes in the development of hypospadias.