[Nephrotic syndrome: don't forget to search for hypothyroidism]

If abnormal thyroid function indices have been reported in patients with nephrotic syndrome, hypothyroidism is exceptional.We report three adult patients (1, 2, 3) with hypothyroidism associated with nephrotic syndrome (minimal change glomerulonephritis [1], idiopathic membranous nephropathy stage I [2], stage II [3]). Glomerulopathy treatment and thyroid hormone replacement therapy were both initiated. Low replacement (1, 2) was sufficient when proteinuria decreased. It was higher when nephrotic syndrome was uncontrolled (3).Excessive thyroxine-binding protein and thyroxine urinary loss generate low rate of free thyroxine and elevated TSH. Systematic thyroid hormonal test is necessary if nephrotic syndrome is severe and prolonged.