Monoclonal Gammopathy of Renal Significance

Patient Information

Monoclonal Gammopathy of Renal Significance (MGRS) is a group of conditions which are diagnosed because of the way the kidney looks under the microscope. The following conditions are included:

  • AH amyloidosis
  • AHL amyloidosis
  • AL amyloidosis
  • C3 glomerulonephritis with monoclonal gammopathy
  • Crystalglobulinaemia
  • Crystal-storing histiocytosis
  • Fibrillary Glomerulonephritis
  • Immunotactoid/Glomerulonephritis with Organised Microtubular Monoclonal Immunoglobulin Deposits (GOMMID)
  • Intracapillary monoclonal IgM without cryoglobulin
  • Intraglomerular/capillary lymphoma/leukaemia
  • Light chain cast nephropathy
  • Light chain proximal tubulopathy, crystalline
  • Light chain proximal tubulopathy, non crystalline
  • Monoclonal Immunoglobulin Deposition Disease (MIDD; includes Light Chain Deposition Disease – LCDD; Heavy Chair Deposition Disease – HCDD; and Light and Heavy Chain Deposition Disease – LHCDD)
  • Proliferative glomerulonephritis with monoclonal immunoglobulin deposits – PGNMID
  • Thrombotic Microangiopathy with monoclonal gammopathy
  • Type 1 cryoglobulinaemic Glomerulonephritis
  • Unclassified MGRS

Monoclonal Gammopathy of Renal Significance (MGRS) is a group of conditions with a wide variety of symptoms. Most people will be diagnosed via blood tests which show an abnormally high level of a certain protein from the bone marrow (“gamma globulin”). Kidney involvement (“renal significance”) is shown either by the finding of protein in the urine or abnormal kidney function tests (i.e. the kidneys are not cleaning the blood normally). Some people may have no symptoms at all and may be diagnosed by routine blood tests. Others may feel very unwell because the bone marrow protein is causing kidney failure. Swelling (particularly in the ankles) is common, due to protein leaking into the urine. If there is too much fluid in the body this can also cause shortness of breath. These symptoms may be associated with all of the MGRS conditions. Other symptoms may be more specific depending on the exact condition.

  • AL Amyloidosis – this condition can affect the kidneys but it can also affect other tissues in the body and so symptoms can vary depending on where the proteins are having an effect. For more information on this condition please go to
  • Light chain cast nephropathy – this condition is due to an underling bone marrow cancer called myeloma. As well as kidney failure other symptoms relate to the abnormal bone marrow such as pain in the bones, tiredness or frequent infections. For more information please go to

If your kidney function is stable and the level of protein leaking through the kidneys is low, your consultant may just monitor your blood tests to see if anything is changing and not prescribe any further treatment. If your kidney function is getting worse and/or the level of protein being lost is increasing, you may be prescribed chemotherapy to suppress the abnormal cells in the bone marrow which are producing the toxic protein. The type of chemotherapy used is the same as for a condition called myeloma but it does not mean that you have cancer.  

More information for patients diagnosed with AL amyloidosis can be found through the National Amyloidosis Centre UK NAC: For patients with light chain cast nephropathy or other MGRS conditions see the following link to Myeloma UK support groups:

Monoclonal gammopathy (MG) is a non-cancerous condition. It is a condition where an abnormal protein is made in the bone marrow. This protein is from a group of immune proteins called gamma globulins or immune globulins. It is also known as a paraprotein or M-protein. It is found in the urine or blood. Most people who have a paraprotein are not found to have problems or symptoms because of it and they are monitored to check that the amount is not changing and it is not causing damage to the body. Very rarely a low level of paraprotein in the blood can affect the kidneys through various ways. When the paraprotein is found to be causing damage to the kidney we call the process Monoclonal Gammopathy of Renal Significance (MGRS). Your kidney specialist will have picked this up by doing a kidney biopsy. When the connection between the bone marrow protein and the kidneys is made some people may benefit from treatment to stop the bone marrow making the paraprotein. Some people with an MG can develop a blood cancer called Myeloma, this is when there are too many cells in the bone marrow producing a paraprotein. In some cases this can cause small blockages in the kidneys and stop the urine flowing through properly. This is called cast nephropathy. In this case chemotherapy is needed to stop the bone marrow from producing the protein as kidney failure can occur quickly.

Monoclonal Gammopathy of Renal Sigificance (MGRS) is a relatively new term for a group of rare diseases. Papers have been published looking at how patients with conditions such as AL amyloidosis are affected and how well treatment with chemotherapy works. However some of the conditions in this group are much rarer than others and so far information has only been published about individual cases. The MGRS Rare Disease Group (RDG) is registering patients in the National Rare Disease Registry (RaDaR). The registry will be used to find suitable participants for future research trials and to look at how effective current treatments are. It will also be used to gather evidence to write guidelines on the recommended diagnosis and treatment for MGRS patients.  If you are interested in finding out more about the registry RaDaR or the activity of the RDG please visit the MGRS RDG page.  

Further information about the conditions covered by the MGRS label can be found at the following links:  


NICE accredited clinical practice guidelines 

Available here

25th Annual Report

Analyses about the care provided to patients at UK renal centres.

Read the report

2022 UKRR AKI Report

A report on the nationwide collection of AKI warning test scores. 

Read the report