The three most abundant MHC and DHC species (in descending order) and their fecal excretion rates (nmol/mouse/day) in HF and HFPL mice respectively were: DHC 22:0, 8.1 ± 0.4 vs 89.4 ± 5.1, P < 0.001; DHC 24:0, 4.9 ± 0.2 vs 87.5 ± 4.9, P < 0.001; DHC 16:0, 4.1 ± 0.2 vs 49.7 ± 3.6, P < 0.001; MHC 22:0, 3.5 ± 0.3 vs 39.1 ± 3.2, P < 0.001; MHC 24:0, 2.0 ± 0.1 vs 36.1 ± 3.0, P < 0.001; MHC 16:0, 1.7 ± 0.1 vs 13.4 ± 1.3, P < 0.001. The gene discussed is HLA-C; the disease is hydrops fetalis.