In:
Journal of the American Society of Nephrology, Ovid Technologies (Wolters Kluwer Health), Vol. 31, No. 1 ( 2020-1), p. 139-147
Abstract:
Most patients with congenital anomalies of the kidney and urinary tract (CAKUT), the leading cause of pediatric ESKD, do not have mutations in any of the approximately 40 CAKUT-causing genes that have been identified to date. The authors studied a family with two siblings with CAKUT that appeared to be caused by an autosomal recessive mutation in an as-yet unidentified gene. Using whole-exome and whole-genome sequencing, they found that the affected children but not healthy family members had a homozygous deletion in the Cobalamin Synthetase W Domain–Containing Protein 1 (CBWD1) gene. They also demonstrated in mice that Cbwd1 protein was expressed in the ureteric bud cells, and that Cbwd1 -deficient mice showed CAKUT. These findings suggest a role for CBWD1 in CAKUT etiology. Background Researchers have identified about 40 genes with mutations that result in the most common cause of CKD in children, congenital anomalies of the kidney and urinary tract (CAKUT), but approximately 85% of patients with CAKUT lack mutations in these genes. The anomalies that comprise CAKUT are clinically heterogenous, and thought to be caused by disturbances at different points in kidney development. However, identification of novel CAKUT-causing genes remains difficult because of their variable expressivity, incomplete penetrance, and heterogeneity. Methods We investigated two generations of a family that included two siblings with CAKUT. Although the parents and another child were healthy, the two affected siblings presented the same manifestations, unilateral renal agenesis and contralateral renal hypoplasia. To search for a novel causative gene of CAKUT, we performed whole-exome and whole-genome sequencing of DNA from the family members. We also generated two lines of genetically modified mice with a gene deletion present only in the affected siblings, and performed immunohistochemical and phenotypic analyses of these mice. Results We found that the affected siblings, but not healthy family members, had a homozygous deletion in the Cobalamin Synthetase W Domain–Containing Protein 1 (CBWD1) gene. Whole-genome sequencing uncovered genomic breakpoints, which involved exon 1 of CBWD1 , harboring the initiating codon. Immunohistochemical analysis revealed high expression of Cbwd1 in the nuclei of the ureteric bud cells in the developing kidneys. Cbwd1 -deficient mice showed CAKUT phenotypes, including hydronephrosis, hydroureters, and duplicated ureters. Conclusions The identification of a deletion in CBWD1 gene in two siblings with CAKUT implies a role for CBWD1 in the etiology of some cases of CAKUT.
Type of Medium:
Online Resource
ISSN:
1046-6673
,
1533-3450
DOI:
10.1681/ASN.2019040398
Language:
English
Publisher:
Ovid Technologies (Wolters Kluwer Health)
Publication Date:
2020
detail.hit.zdb_id:
2029124-3
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