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.