Altered expression of Crb2 in podocytes expands a variation of CRB2 mutations in steroid-resistant nephrotic syndrome

作者：Udagawa Tomohiro; Jo Tohaku; Yanagihara Takeshi; Shimizu Akira; Mitsui Jun; Tsuji Shoji; Morishita Shinichi; Onai Reiko; Miura Kenichiro; Kanda Shoichiro; Kajiho Yuko; Tsurumi Haruko; Oka Akira; Hattori Motoshi; Harita Yutaka

来源：Pediatric Nephrology, 2017, 32(5): 801-809.

DOI：10.1007/s00467-016-3549-4

• Steroid-resistant nephrotic syndrome
• Crb2
• Podocyte
• Slit diaphragm

Steroid-resistant nephrotic syndrome (SRNS) is a genetically heterogeneous disorder for which more than 25 single-gene hereditary causes have been identified.
Whole exome sequencing was performed in a 3-year-old girl with SRNS. We analyzed the expression of Crb2 and slit diaphragm molecules in the patient's glomeruli, and compared it with that of controls or other nephrotic patients.
Whole-exome analysis identified novel compound heterozygous mutations in exons 10 and 12 of CRB2 (p.Trp1086ArgfsX64 and p.Asn1184Thr, each from different parents; Asn1184 within extracellular 15th EGF repeat domain). Renal pathology showed focal segmental glomerulosclerosis with effaced podocyte foot processes in a small area, with significantly decreased Crb2 expression. Molecules critical for slit diaphragm were well-expressed in this patient's podocytes. Crb2 expression was not altered in the other patients with congenital nephrotic syndrome with NPHS1 mutations.
These findings demonstrate that Crb2 abnormalities caused by these mutations are the mechanism of steroid-resistant NS. Although CRB2 mutations previously found in SRNS patients have been clustered within the extracellular tenth EGF-like domain of this protein, the present results expand the variation of CRB2 mutations that cause SRNS.

• 出版日期2017-5