CRISPR doesn't exist yet for treating MGUS/SMM/MM which can be associated with a number of genetic mutations in the cells that create IgM and other proteins. There are numerous papers on MGUS, IgA, IgG, IgM, neuropathies, and many others in ResearchGate. These and NIH funded publications include background info and treatments for mostly MM. MGUS and most SMM are waiting games. The risk for progression of MGUS to MM is about 1%/year, so for most people treatment is not needed. I have IgA Kappa MGUS (for 8 years, 70 yo) and some (likely associated) polyneuropathy that I "treat" by staying active, hiking, biking, woodturning. Filtering the kappa or lambda proteins from the bloodstream would decrease damage, including if someone has amyloidosis, but that dialysis would have its own issues. I have 1q21 gain, which means one of the mutations that I have is an extra gene on the long arm (q) of chromosome 21 based on my bone marrow biopsy.