Objective: To report the clinical characteristics and a new CRB2 gene mutation of a girl with steroid resistant nephrotic syndrome(SRNS).
Methods: Clinical data and family histories of a girl with SRNS were collected.Renal biopsy and gene anylysis were conducted.
Results: A Chinese girl aged 7.25 years was referred to our hospital with detection of proteinuria for 3 days. A series of detections were performed and the child was diagnosed with nephrotic syndrome. The treatment of 4 weeks of prednisone at 2mg/kg was started but it had no effect on her nephrotic-range proteinuria. Then the girl was referred to another hospital and was treated with CTX twice ,10mg/kg/d×2days per time. The amount of proteinuria accended to 4504mg/24h when the girl came back to our hospital 3 month later. Her farther told us that the girl’s little brother aged one-year-old was found to have proteinuria too.Methylprednisolone pulse therapy was performed,500mg×3 days, the amount of proteinuria decended to 3805mg/24h. We diagnosed it as SRNS. The renal biopsy was performed 4 months after the first interview. The renal pathological results showed the glomeruli spherical hyperplasia with segmental sclerosis. A genetic analysis was also performed because the little brother was detected proteinuria. The genetic analysis identified the CRB2 gene mutation in the girl. A mutation of c.2277G＞A(p.W759X) was found to inherit from her mother and it was reported to relate to hereditary nephrosis. A mutation of C.3190C＞T(p.P1064S) was inherited from her father and it was not yet reported in HGMD Professional database.
Conclusion: The patient was a SRNS with pathological manifestation as glomeruli spherical hyperplasia with segmental sclerosis caused by CRB2 gene mutation. Genetic analysis was advised to be done when a patient with nephrotic syndrome had a family history or steroid resistance.