SOX9 and hydrops fetalis: (ii) Clusters with strong expression of HF and ORS marker grouped in HF1 and HF2, with HF1 group encompassing clusters 1, 5 and 11 showing strong ORS marker expression and clusters 3, 6, 8 and 9 grouped in HF2, also showing ORS characteristics with additional marker expression, e.g. cluster 6 was enriched for HF stem cell marker, such as Lhx2, Sox9 and Nfatc1.