Immunoglobulin C mu gene restriction fragment length polymorphisms associated with chronic renal failure

The DNA's of 41 patients with various forms of renal disease and of 52 controls were investigated for restriction fragment length polymorphisms (RFLP), using a probe recognising the immunoglobulin Cmu heavy chain gene. With the restriction endonuclease Sst 1, 50 of the controls and 12 of the patients had the expected single 4.3 kilobase (kb) fragment. The remaining 29 patients and 2 controls displayed two patterns of banding, 8 patients and 1 control had a 6.8 kb band in addition to the 4.3 kb, and 21 patients and 1 control had a single band of 5.1 kb. In addition, a significant association between high creatinine levels (greater than 150 mumol/l) and abnormal bands was found (21/25 patients with high levels had abnormal bands compared with only 5/16 patients with normal levels). These results are evidence for an association between the human immunoglobulin heavy chain region and renal disease and they apparently confirm an association already reported at the protein level. However, the new RFLP bands, although reproducible and restricted to renal patients, occur in an area where few polymorphisms would be expected. Further, the association with high creatinine suggests some subtle interaction between the creatinine pathway and this area of the human chromosome.