| 1. |
- Draaken, Markus, et al.
(author)
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Classic Bladder Exstrophy: Frequent 22q11.21 Duplications and Definition of a 414 kb Phenocritical Region
- 2014
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In: Birth Defects Research. Part A: Clinical and Molecular Teratology. - : Wiley. - 1542-0760 .- 1542-0752. ; 100:6, s. 512-517
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Journal article (peer-reviewed)abstract
- Background: Classic bladder exstrophy (CBE) is the most common form of the bladder exstrophy and epispadias complex. Previously, we and others have identified four patients with a duplication of 22q11.21 among a total of 96 unrelated CBE patients. Methods: Here, we investigated whether this chromosomal aberration was commonly associated with CBE/bladder exstrophy and epispadias complex in an extended case-control sample. Multiplex ligation-dependent probe amplification and microarray-based analysis were used to identify 22q11.21 duplications in 244 unrelated bladder exstrophy and epispadias complex patients (including 217 CBE patients) and 665 healthy controls. Results: New duplications of variable size were identified in four CBE patients and one control. Pooling of our previous and present data (eight duplications in 313 CBE patients) yielded a combined odds ratio of 31.86 (95% confidence interval, 4.24-1407.97). Array-based sequence capture and high-throughput targeted re-sequencing established that all breakpoints resided within the low-copy repeats 22A to 22D. Comparison of the eight duplications revealed a 414 kb phenocritical region harboring 12 validated RefSeq genes. Characterization of these 12 candidate genes through whole-mount in situ hybridization of mouse embryos at embryonic day 9.5 suggested that CRKL, THAP7, and LZTR1 are CBE candidate genes. Conclusion: Our data suggest that duplication of 22q11.21 increases CBE risk and implicate a phenocritical region in disease formation. (C) 2014 Wiley Periodicals, Inc.
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| 2. |
- Reutter, Heiko, et al.
(author)
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Genome-wide association study and mouse expression data identify a highly conserved 32kb intergenic region between WNT3 and WNT9b as possible susceptibility locus for isolated classic exstrophy of the bladder.
- 2014
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In: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 23:20, s. 5536-5544
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Journal article (peer-reviewed)abstract
- Bladder Exstrophy-Epispadias Complex (BEEC), the severe end of the uro-rectal malformation spectrum, has a profound impact on continence as well as sexual and renal functions. It is widely accepted that for the majority of cases the genetic basis appears to be multifactorial. Here, we report the first study which utilizes genome-wide association methods to analyze a cohort comprising patients presenting the most common BEEC form, classic bladder exstrophy (CBE), to identify common variation associated with risk for isolated CBE. We employed discovery and follow-up samples comprising 218/865 cases/controls and 78 trios in total, all of European descent. Our discovery sample identified a marker near SALL1, showing genome-wide significant association with CBE. However, analyses performed on follow-up samples did not add further support to these findings. We were also able to identify an association with CBE across our study samples (discovery: P=8.88 x 10(-5); follow-up: P=0.0025; combined: 1.09 x 10(-6)) in a highly conserved 32kb intergenic region containing regulatory elements between WNT3 and WNT9B. Subsequent analyses in mice revealed expression for both genes in the genital region during stages relevant to the development of CBE in humans. Unfortunately, we were not able to replicate the suggestive signal for WNT3 and WNT9B in a sample that was enriched for non-CBE BEEC cases (P=0.51). Our suggestive findings support the hypothesis that larger samples are warranted to identify association of common variation with CBE.
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| 3. |
- Korberg, Izabella Baranowska, et al.
(author)
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WNT3 involvement in human bladder exstrophy and cloaca development in zebrafish
- 2015
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In: Human Molecular Genetics. - : Oxford University Press (OUP). - 0964-6906 .- 1460-2083. ; 24:18, s. 5069-5078
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Journal article (peer-reviewed)abstract
- Bladder exstrophy, a severe congenital urological malformation when a child is born with an open urinary bladder, is the most common form of bladder exstrophy-epispadias complex (BEEC) with an incidence of 1: 30,000 children of Caucasian descent. Recent studies suggest that WNT genes may contribute to the etiology of bladder exstrophy. Here, we evaluated WNT-pathway genes in 20 bladder exstrophy patients using massively parallel sequencing. In total 13 variants were identified in WNT3, WNT6, WNT7A, WNT8B, WNT10A, WNT11, WNT16, FZD5, LRP1 and LRP10 genes and predicted as potentially disease causing, of which seven variants were novel. One variant, identified in a patient with a de novo nonsynonymous substitution in WNT3 (p.Cys91Arg), was further evaluated in zebrafish. Knock down of wnt3 in zebrafish showed cloaca malformations, including disorganization of the cloaca epithelium and expansion of the cloaca lumen. Our study suggests that the function of the WNT3 p.Cys91Arg variant was altered, since RNA overexpression of mutant Wnt3 RNA does not result in embryonic lethality as seen with wild-type WNT3 mRNA. Finally, we also mutation screened the WNT3 gene further in 410 DNA samples from BEEC cases and identified one additional mutation c.638G> A (p.Gly213Asp), which was paternally inherited. In aggregate our data support the involvement of WNT-pathway genes in BEEC and suggest that WNT3 in itself is a rare cause of BEEC.
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