The Case: Chronic Kidney Disease Unmasked by Single-Subject Research.

We present a 42-year-old man with a BMI of 32, who was referred because of proteinuria and decreased renal function. We were impressed by his markedly muscular physique. A renal biopsy was performed, which showed focal segmental glomerular sclerosis (FSGS). Is this patient merely an obese person with FSGS or is something else going on here? We performed extensive clinical and laboratory examinations, genetic testing, and anthropometric data monitoring over time. We transferred our methodology for routine FSGS mutation screening (Sanger sequencing) to the Ion Torrent PGM platform with a new custom-targeted NGS gene panel (Ion Ampliseq FSGS panel) and tested the performance of the system in two cohorts of patients with FSGS. We discuss FSGS in bodybuilders, including possible mechanisms, and review the literature.