--is hereditary; quite a lot is acquired, generally as a cross-effect of monoclonal gammopathy or other immune blood disorders, which is why they want the hematological work-up.

Take a look at the following from the Washington University at St. Louis neuromuscular website--it's written in doctorese shorthand, but very comprehensive:

http://neuromuscular.wustl.edu/antib...imdem.html#mag

http://neuromuscular.wustl.edu/antibody/mprotein.htm