Lipoic acid supplementation associated with neural epidermal growth factor-like 1 (NELL1)–associated membranous nephropathy

Lipoic acid (alpha lipoic acid, thioctic acid) is a popular over-the-counter antioxidant and insulin-mimetic supplement under investigation in a variety of conditions including multiple sclerosis, diabetes, and schizophrenia. Unfortunately, high-grade proteinuria was an unexpected adverse event specific to the treatment arm of our clinical trial investigating lipoic acid supplementation in patients with multiple sclerosis. This observation led to detection of similar patients in our nephrology practice. Here, we describe four biopsy-proven cases of neural epidermal growth factor-like 1 (NELL1)–associated membranous nephropathy following lipoic acid supplementation and a fifth suspected case. Discontinuation of lipoic acid and supportive therapy resulted in remission.