Steroid-resistant nephrotic syndrome as the initial presentation of nail-patella syndrome: a case of a de novo LMX1B mutation

BMC Nephrology

Case Report

Tsuyoshi Isojima¹  Sachiko Kitanaka¹  Yutaka Harita¹  Atsuko Fujii²  Ryo Ishida²  Keiichi Tamagaki²  Tetsuro Kusaba²  Yuu Mihara²  Tomohiro Nakata²  Yoshimoto Inoue³  Chiaki Kanda³ 

[1] Department of Pediatrics, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113-8655, Tokyo, Japan;Division of Nephrology, Department of Medicine, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, 602-8566, Kyoto, Japan;Division of Nephrology, Kyoto Min-iren Chuo Hospital, 16-1 Nishinokyo Kasuga-cho, Nakagyo-ku, 604-8453, Kyoto, Japan;

关键词: Nail-patella syndrome;    LMX1B;    Steroid-resistant nephrotic syndrome;   

DOI  :  10.1186/s12882-017-0516-7

 received in 2016-05-31, accepted in 2017-03-15,  发布年份 2017

来源: Springer

【 摘 要 】

BackgroundNail-patella syndrome (NPS) is an autosomal dominant disorder caused by mutations in the LMX1B gene and is characterized by nail dysplasia, skeletal abnormalities, and nephropathy. We herein report a case of steroid-resistant nephrotic syndrome (SRNS) prior to overt orthopedic symptoms in a patient with NPS.Case presentationA 24-year-old woman presented to our hospital with knee pain. She had poorly developed nails, hypoplastic patellas, dislocation of the elbows, and iliac horns in the pelvis. At the age of 7, she developed nephrotic syndrome and was diagnosed with primary focal segmental glomerulosclerosis by renal biopsy. She received long-term corticosteroid therapy with no obvious response. Her clinical course and orthopedic manifestations indicated NPS, and a genetic analysis showed a de novo mutation in the LMX1B gene (c.819 + 1G > A). Nephropathy in this case was considered to be associated with NPS. Therefore, we discontinued corticosteroids without the exacerbation of nephrotic syndrome.ConclusionsPatients with NPS may develop nephrotic syndrome prior to overt orthopedic symptoms and only show non-specific findings in renal biopsy at an early stage of NPS nephropathy. Hereditary nephrotic syndrome, often presenting as childhood-onset SRNS, may also be difficult to diagnose in patients with the following conditions: renal symptoms prior to overt extrarenal symptoms, de novo mutations, and non-specific findings in renal biopsy. Therefore, in the management of SRNS in children, we need to reconsider the possibility of hereditary diseases such as NPS even without a family history.

【 授权许可】

CC BY   
© The Author(s). 2017