Medicines for MGUS (monoclonal gammopathy)

What it is

MGUS stands for monoclonal gammopathy of undetermined significance. It describes the presence of a small amount of an abnormal protein (a "paraprotein" or "M protein"), made by a group of plasma cells, in the blood — without any of the problems that define related conditions such as myeloma. It is common, particularly in older people, and is usually found by chance when blood tests are done for another reason. By itself, MGUS causes no symptoms and needs no treatment. Its importance is that, in a small proportion of people each year, it can progress to a related condition — most notably myeloma, or occasionally other blood conditions — which is why people with MGUS are monitored over time. The great majority of people with MGUS never develop these conditions and it does not shorten their life, so understanding it as a "watch and monitor" finding, rather than a disease, is reassuring.

How it is treated

MGUS itself is not treated, as it causes no problems. The approach is regular monitoring — usually with periodic blood tests — to check the level of the abnormal protein and to look out for any signs that it might be progressing, so that if a related condition such as myeloma were to develop, it could be picked up and treated early. How often monitoring is done depends on the individual's level of risk, which is estimated from factors such as the amount and type of the paraprotein. People are advised of symptoms to report between check-ups (such as bone pain, unexplained tiredness, recurrent infections, or unusual bruising). The overwhelmingly reassuring message is that most people with MGUS remain well, never develop a related condition, and simply have their blood monitored. Care is guided by a GP and, where appropriate, a haematologist.