GJC2 and lymphedema: Likewise, venous valves are absent in virtually all peripheral veins of Cx47−/− mice, but those mice exhibit normal numbers of LVs and normal expression of canonical LV markers without reflux of injected tracer,19,22 which is perplexing because patients with Cx47 missense mutations develop lymphedema;6,7,9 measurements of LV function in Cx47−/− mice are also needed.