Copy Number Variant Analysis and Genome-wide Association Study Identify Loci with Large Effect for Vesicoureteral Reflux
Authors: Verbitsky Miguel , Krithivasan Priya , Batourina Ekaterina , Khan Atlas , Graham Sarah E. , Marasà Maddalena , Kim Hyunwoo , Lim Tze Y. , Weng Patricia L. , Sánchez-Rodríguez Elena , Mitrotti Adele , Ahram Dina F. , Zanoni Francesca , Fasel David A. , Westland Rik , Sampson Matthew G. , Zhang Jun Y. , Bodria Monica , Kil Byum Hee , Shril Shirlee , Gesualdo Loreto , Torri Fabio , Scolari Francesco , Izzi Claudia , van Wijk Joanna A.E. , Saraga Marijan , Santoro Domenico , Conti Giovanni , Barton David E. , Dobson Mark G. , Puri Prem , Furth Susan L. , Warady Bradley A. , Pisani Isabella , Fiaccadori Enrico , Allegri Landino , Degl'Innocenti Maria Ludovica , Piaggio Giorgio , Alam Shumyle , Gigante Maddalena , Zaza Gianluigi , Esposito Pasquale , Lin Fangming , Simões-e-Silva Ana Cristina , Brodkiewicz Andrzej , Drozdz Dorota , Zachwieja Katarzyna , Miklaszewska Monika , Szczepanska Maria , Adamczyk Piotr , Tkaczyk Marcin , Tomczyk Daria , Sikora Przemyslaw , Mizerska-Wasiak Malgorzata , Krzemien Grazyna , Szmigielska Agnieszka , Zaniew Marcin , Lozanovski Vladimir J. , Gucev Zoran , Ionita-Laza Iuliana , Stanaway Ian B. , Crosslin David R. , Wong Craig S. , Hildebrandt Friedhelm , Barasch Jonathan , Kenny Eimear E. , Loos Ruth J.F. , Levy Brynn , Ghiggeri Gian Marco , Hakonarson Hakon , Latos-Bieleńska Anna , Materna-Kiryluk Anna , Darlow John M. , Tasic Velibor , Willer Cristen , Kiryluk Krzysztof , Sanna-Cherchi Simone , Mendelsohn Cathy L. , Gharavi Ali G. 
Published: February 2021

Significance Statement
Vesicoureteral reflux (VUR) is associated with progressive kidney disease. Familial aggregation supports a hereditary basis; however, its genetic architecture remains to be elucidated. The largest VUR copy number variant analysis and genome-wide association study to date accounts for multiple modes of inheritance and sex-specific effects in VUR, identifying three study-wide significant and five suggestive loci with large effects, containing canonical developmental genes including WDPCP and WNT5A. Results of experiments in mice support novel roles of Wnt5a in urogenital development. Altogether, 6% of patients carried high-risk genotypes. These findings have important implications for VUR screening.

Background
Vesicoureteral reflux (VUR) is a common, familial genitourinary disorder, and a major cause of pediatric urinary tract infection (UTI) and kidney failure. The genetic basis of VUR is not well understood.

Methods
A diagnostic analysis sought rare, pathogenic copy number variant (CNV) disorders among 1737 patients with VUR. A GWAS was performed in 1395 patients and 5366 controls, of European ancestry.

Results
Altogether, 3% of VUR patients harbored an undiagnosed rare CNV disorder, such as the 1q21.1, 16p11.2, 22q11.21, and triple X syndromes ((OR, 3.12; 95% CI, 2.10 to 4.54; P=6.35×10−8) The GWAS identified three study-wide significant and five suggestive loci with large effects (ORs, 1.41–6.9), containing canonical developmental genes expressed in the developing urinary tract (WDPCP, OTX1, BMP5, VANGL1, and WNT5A). In particular, 3.3% of VUR patients were homozygous for an intronic variant in WDPCP (rs13013890; OR, 3.65; 95% CI, 2.39 to 5.56; P=1.86×10–9). This locus was associated with multiple genitourinary phenotypes in the UK Biobank and eMERGE studies. Analysis of Wnt5a mutant mice confirmed the role of Wnt5a signaling in bladder and ureteric morphogenesis.

Conclusions
These data demonstrate the genetic heterogeneity of VUR. Altogether, 6% of patients with VUR harbored a rare CNV or a common variant genotype conferring an OR >3. Identification of these genetic risk factors has multiple implications for clinical care and for analysis of outcomes in VUR.