Case Report
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. May 6, 2021; 9(13): 3056-3062
Published online May 6, 2021. doi: 10.12998/wjcc.v9.i13.3056
Crumbs homolog 2 mutation in two siblings with steroid-resistant nephrotic syndrome: Two case reports
Jing Lu, Yan-Nan Guo, Li-Qun Dong
Jing Lu, Yan-Nan Guo, Li-Qun Dong, Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu 610041, Sichuan Province, China
Author contributions: Lu J and Dong LQ contributed to the conceptualization of the report, drafted, and revised the article; Lu J, Guo YN, and Dong LQ contributed to data curation.
Informed consent statement: Informed consent was obtained from the guardian of the patient for the publication of this report.
Conflict-of-interest statement: The authors declare that they have no conflicts of interest.
CARE Checklist (2016) statement: The authors have read the CARE Checklist (2016), and the manuscript was prepared and revised according to the CARE Checklist (2016).
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Li-Qun Dong, MD, PhD, Professor, Department of Pediatrics, West China Second University Hospital, Sichuan University, No. 20 Section 3 South Renmin Road, Chengdu 610041, Sichuan Province, China. dongliqun@scu.edu.cn
Received: November 3, 2020
Peer-review started: November 3, 2020
First decision: February 12, 2021
Revised: February 22, 2021
Accepted: March 11, 2021
Article in press: March 11, 2021
Published online: May 6, 2021
Processing time: 169 Days and 21.6 Hours
Abstract
BACKGROUND

Crumbs homolog 2 (CRB2) is a recently discovered gene that is closely related to the maintenance of normal polarity in podocytes; mutations can directly lead to steroid-resistant nephrotic syndrome (SRNS). However, the characteristics of nephrotic syndrome (NS) caused by CRB2 mutations have not been described.

CASE SUMMARY

We report a novel compound heterozygous mutation of the CRB2 gene in two siblings with SRNS. The two siblings had edema, proteinuria, hypoproteinemia and hyperlipidemia. Both their father and mother had normal phenotypes (no history of NS). Whole exon sequencing (WES) of the family showed a novel compound heterozygous mutation, c.2290 (exon 8) C > T and c.3613 (exon 12) G > A. Glucocorticoid therapy (methylprednisolone pulse therapy or oral prednisone) and immunosuppressive agents (tacrolimus) had no effect. During a 3-year follow-up after genetic diagnosis by WES, proteinuria persisted, but the patient was healthy.

CONCLUSION

CRB2 mutations related to SRNS often occur in exons 7, 10, and 12. Clinical manifestations of SRNS caused by CRB2 mutations are often less severe than in other forms of SRNS.

Keywords: Steroid-resistant nephrotic syndrome; Crumbs homolog 2; Proteinuria; Compound heterozygous mutation; Glomerulosclerosis; Renal biopsy; Case report

Core Tip: Crumbs homolog 2 (CRB2) mutation is related to early-onset steroid-resistant nephrotic syndrome (SRNS). We here report two siblings with a novel compound heterozygous CRB2 mutation. We also reviewed the literature and found that CRB2 mutations related to SRNS often occur in exons 7, 10 and 12. Clinical manifestations of SRNS caused by CRB2 mutations, such as edema, are often less severe than in other forms of SRNS.