Renal tubular dysfunctions have been described previously with increasing frequency in patients with β-TM.22 Many studies have demonstrated a proximal tubular damage, leading to increased urinary excretion of NAG, beta-2 microglobulin, and LMW proteins.2,23 The contemporary presence of proteinuria, aminoaciduria, low urine osmolality24 and also hyperuricosuria (54%) with renal uric acid wasting25 suggest a more complex damage. Here, B2M is linked to renal tubule disorder.