Isolated Proteinuria Caused by Gene Mutations: A Case Report and Review of the Literature.

Mutations in the cubilin () gene commonly cause Imerslund-Gräsbeck syndrome, while isolated proteinuria as a result of variations is rarely reported. The clinical manifestation is mainly chronic isolated proteinuria in the non-nephrotic range. However, findings to date suggest that isolated proteinuria associated with abnormalities in the gene is benign and does not affect long-term prognosis of kidney function. We identified 2 patients with isolated proteinuria triggered by compound heterozygous mutations. Renal functions of both patients remained normal over a 10-year follow-up period, supporting the benign nature of proteinuria caused by gene variations. Two novel mutation sites were detected, expanding the genotypic spectrum of variations. In addition, etiology, pathogenesis, clinical manifestations, auxiliary examination, and treatment of the condition were reviewed, with the aim of providing further guidance for clinical management.