Nell1 as Target Antigen for Mercury Related Membranous Nephropathy: A Case Report

Membranous nephropathy constitutes 30% of adult nephrotic syndrome. Of all cases of membranous nephropathy, primary membranous nephropathy is commonest. Mercury is known to be a cause of secondary membranous nephropathy. There is no human data on the pathophysiology of mercury-related membranous nephropathy, but animal studies suggested an autoimmune mechanism behind it. There is no data to the best of our knowledge about target antigen for mercury-related membranous nephropathy. We are reporting a case of NELL-1 positive mercury-related membranous nephropathy that started resolving after stopping siddha medication and taking antiproteinuric. There was also concomitant euthyroid lymphocytic thyroiditis with anti-TPO positive, which started after exposure to siddha medication, which suggests systemic autoimmune phenomenon due to mercury exposure.

Automated summary

Membranous nephropathy accounts for 30% of adult nephrotic syndrome cases, with primary membranous nephropathy being the most common. Mercury exposure is known to cause secondary membranous nephropathy, although the exact pathophysiology of mercury-related membranous nephropathy is not yet understood. We reported a case of NELL-1 positive mercury-related membranous nephropathy that showed improvement after cessation of siddha medication and antiproteinuric treatment, along with concomitant euthyroid lymphocytic thyroiditis suggesting a systemic autoimmune phenomenon due to mercury exposure.