Is C1q nephropathy associated with a WDR19 gene mutation? A case report

Background: Even though complement 1q nephropathy (C1qN) was first introduced in 1985, this entity is still unknown and recognized by clinicians due to its rare prevalence (0.2 – 2.5 %) and insufficient emphasis. Description of the case: A 50-year-old woman was incidentally found to have non-nephrotic proteinuria with a normal glomerular filtration rate. Renal biopsy revealed C1qN with severe fibrosis. The presence of consanguinity and kidney diseases in family members of the patient led to genetic research, and homogenous mutation of c.991G>T (p.G331C) in the WD-repeat domain 19 (WDR19) gene was found. The same homozygous and heterozygous mutations in the WDR gene were found in the relatives of our patient with kidney diseases. One year of follow-up with methylprednisolone and mycophenolate mofetil treatment resulted in partial remission of the kidney disease. Conclusion: Renal biopsy for patients with non-nephrotic proteinuria without delay is suggested as it might be a surrogate marker of severe injury. Genetic mutations in the WDR19 gene should be searched for C1qN pathogenesis. This is the first adult case report on C1qN from Turkey.HIPPOKRATIA 2021, 25 (2):87-90.