MAP2K6 and hydrops fetalis: To test the hypothesis that genetic variation in the Map2k6 gene was causal for accumulation of hepatic TAG, male C57BL/6J mice were administered 1 × 1012 PFU/mouse adeno‐associated virus (AAV) expressing either GFP or Map2k6 cDNAs under a thyroid‐binding globulin (TBG) promoter and subsequently fed a HF/HS diet for 8 weeks (Fig 5D).