Uromodulin gene polymorphisms in patients with cast nephropathy in multiple myeloma

Abstract

Aim. To investigate the nature of mutations in exons 4 and 5 of the uromodulin (UM) gene, including in the area encoding the domain of 8 cysteines (D8C), in patients with multiple myeloma (MM) with the secretion of monoclonal light chains (LC) in cast nephropathy (CN) and without kidney injury. Subjects and methods. The investigation enrolled 24 patients in MM remission, who were observed to have monoclonal LC secretion at onset. Group 1 included 14 patients with CN; Group 2 consisted of 10 patients with normal renal function (a comparison group). The compared groups did not differ in the number of serum and urinary monoclonal LCs. Genomic DNA was extracted from the peripheral blood samples of patients. The nucleotide sequence of exons 4 and 5 of the UM gene was determined by the Sanger method. Results. No differences were found in the frequency of polymorphisms depending on the severity of kidney injury. The missense mutation p.142R>R/Q in the UM gene, which had not been previously described, was discovered. Conclusion. The patients with MM were not found to have statistically significant differences in the frequency and nature of polymorphisms of exons 4 and 5 in the UM gene, including in the area encoding D8C, in CN without kidney injury.

Keywords

• uromodulin
• cast nephropathy
• multiple myeloma