Clinical and genetic diagnosis of a patient with focal segmental glomerulosclerosis due to a novel variant of the ANLN gene.

Focal segmental glomerulosclerosis (FSGS), a common cause of nephrotic syndrome, is diagnosed by renal biopsy showing focal segmental sclerosis with foot-process effacement. It has a poor prognosis and can rapidly progress to end-stage kidney disease (ESKD). While the etiology of FSGS is largely unknown, many genes have been linked to the familial form of the condition. One of its subtypes, FSGS8, is caused by a heterozygous mutation in the ANLN gene on chromosome 7p14. However, reports of disease-causing ANLN variants in the literature are scarce. Here, we report a novel variant of ANLN in a Chinese family with FSGS. The proband was in hospital for proteinuria and the laboratory tests elevated levels of serum creatinine and uric acid. Histopathology study of renal biopsy showed FSGS. Genetic testing based on whole-exome sequencing (WES) was performed to explore the molecular basis. A heterozygous pathogenic variant of the ANLN gene, NM_018685 c.2343G > C, was identified in the affected patients and further confirmed by Sanger sequencing. This variant leads to a missense mutation in the anillin protein, altering its structure. This novel pathogenic variant of the ANLN gene provides a molecular basis for FSGS8 and expands the known mutation spectrum for FSGS.