I also have the same issues. I was told a lot of thinks like it’s in my head so on kinda like I’m crazy. All my symptoms are the same except mine isn’t bleeding ulcers tho it’s diverticulitis. Lost a lot of feeling in one foot so on so forth. It has cause me to gain weight due to I can’t do my daily gym routine I use to do before getting MGUS. I wish they would quit saying there is no symptoms with it. It’s just not true. You are labeled as a hypochondriac before it’s actually found and turned to myeloma. So here is the thing they found mine only cause my dad and his 2 sisters passed from it all within 6 months. Btw they all had same symptoms for years they actually told my dad and one of my Aunts they needed to put them on depression medication. So then my son was diagnosed with stage 4 lymphoma 6montus after my Aunt passed. my doctor decided to run blood serum test. Now I see an oncologist every 4 months. Because it was caught. Some days are good some days are unbearable. As to your question definitely can inherit the mutated gene.