One study evaluated arm lymphedema defined by bioimpedance ratio and found that an IL4 polymorphism was associated with arm lymphedema [13•], while another study observed no associations between IL4 and arm lymphedema phenotype defined by > 5% limb volume increase and lymph fluid level of ≥ + 10 at 12 months following breast cancer surgery, but did observe an association with lymphedema symptoms [4••]. The gene discussed is IL4; the disease is lymphedema.