I've had MGUS for 8 years. I had a BMB this summer and plasma level was 15% and 1q21 gain (chromosome 1, one replication at location 21) which should have me in the SMM range, but doctor says still MGUS. My kappa is almost 300 and kappa/lambda ~28. I'm 70 and still asymptomatic. The 1q21 gain is associated with somewhat higher chance of it turning to MM and less responsive to treatment, but about 40% of people that have MM have 1q21 gain or amplification (tripled rather than doubled). I try to spend my time doing fun stuff, hobbies, biking, cooking, and not stressing over what might be, because MGUS is a waiting game. Even if someone has SMM it may not morph to MM, and if it does then the avg. prognosis is still for years of biking. ResearchGate has a lot of peer reviewed papers on MGUS, SMM, and MM research.