MSK is a rare disease, according to medical research journals and the Office of Rare Disorders. Very little research has been done on MSK, so very little is known about, and there is a ton of misinformation on the internet about the disease, discounting it as unpainful and benign.
Researchers do not know yet what causes MSK. There have been some genetic links, but for the most part, most research that I have read agree it is NOT genetic. Therefore, it is likely your children have it. However, if you want to know for sure, all you have to do is take them to the doctor and have them get a CT scan. The CT scan will allow the DR to make a diagnosis.
There are varying degrees of MSK...some people never have any serious symptoms, maybe just a few stones, but nothing major. Others suffer from severe chronic pain....all day every day. It destroys their lives', resulting in loss of employment and divorces. Very few doctors actually understand MSK, the pain it causes, and the destruction it does to the kidneys. This leads many doctors to label patients as drug-seekers. Some doctors go as far as to say their patients are faking the pain or overreacting. I should also note that MSK is a progressive condition...at least that is what medical research and patients report. Again, this varies from person-to-person. You may never get any worse. Or, you may get more calcifications, more stones, and more infections. You should be getting check ups with imaging studies (like ultrasounds) every 6 months to know how the MSK is progressing, if at all. And again, if you are worried about your children having it, talk to the pediatrician about setting up a CT scan. MSK is pretty serious and should not be taken lightly. Even if your own experience has been okay, the severity varies for each person.
In my own experience, I went through a lot to get a proper diagnosis of sponge kidney. I first went to an urgent care center, because I had symptoms of a severe UTI for a week, and I was in such excruciating pain I could not sleep, work, eat, etc. I knew if I went to the ER, I would have to wait 4+hrs, but if I went to an urgent care center I'd be seen quickly. The pain was so bad, I couldn't wait in an ER. Additionally, I wasn't dying, and the ER should be reserved for those with severe trauma. After explaining my symptoms, the GP started making comments about me faking because my symptoms were too severe and varied to be just a stone. He said if I had a kidney stone, I'd be at the hospital from pain...I said I was in too much pain to wait there, when I could just see him at the urgent care center. After making other rude and extremely inappropriate comments about my genitals (totally inappropriate...he thought he was making funny jokes, I guess), I went to a urologist. The uro did a CT...turned out I had THREE stones in my kidney and a severe infection, which took over a month to kill. Turned out I also have MSK. Right now, I suffer in flare ups....I may suffer for months with chronic pain, but then be mostly pain free for a couple of months. I should also note that kidney stones can be scary....especially when they won't pass. When I had my CT, I had 3 stones....I have only passed 1, and it is almost a full year later. So, having stones can be haunting, but the pain of a stone passing is nothing compared to the chronic, daily abdominal and urinary pain of a MSK sufferer.