Pedigree showing family members with multiple myeloma or monoclonal gammopathy of undetermined significance (MGUS) in a pattern consistent with autosomal dominant transmission. The pedigree shows a decrease in the age of onset of prostate cancer, MGUS, and multiple myeloma from generation II to generation III. The arrow indicates the proband. The double horizontal line between family members II-1 and II-2 indicates that they are identical twins. Reprinted from Lynch et al²  with permission.