Inclusion Body Myositis is more common in men than in women and usually occurs after the age of 50. IBM usually begins with weakness in th muscles of the wrists, fingers and thinghs. The muscles that lift the front of the foot may also be affected leading to falls. In IBM the weakness may not be the same on both sides of the body. IBM is diagnosed only by a muscle biopsy, which will slow abnormal “inclusion” cells. Unlike PM, DM and JDM, in very rare cases, a form of IBM can be hereditary.