Evaluation of the gene in the pathogenesis of bladder exstrophy in a Swedish cohort.

Bladder exstrophy is a congenital closure defect of the urinary bladder with a profound effect on morbidity. Although the malformation is usually sporadic, a genetic background is supported by an increased recurrence risk in relatives, higher concordance rates in monozygotic twins and several associated chromosomal aberrations. Recently, the gene was presented as a candidate gene for bladder exstrophy and epispadias complex (BEEC) development in two different studies. In our study, we screened for genetic variants in the gene in DNA from 125 Swedish patients using Sanger sequencing and array-CGH analysis. In addition, we evaluated expression in RNA of human bladder during embryonic and fetal weeks 5-10 relative to that in lung tissue (week 9). In total, 21 single-nucleotide variants were identified, including a potentially novel missense variant, c.137C>G p.(Ala46Gly), substituting a conserved amino acid. This variant was inherited from an unaffected mother. No structural variants were identified. RNA sequencing revealed mRNA expression during the critical time frame of human bladder development. In conclusion, we did not detect any known or likely pathogenic variants in the gene in 125 Swedish BEEC patients, indicating that variation in the gene is not a common genetic mechanism of BEEC development in the Swedish population.