A detailed analysis of either mutation in MYBPC3 (c.1358dupC, c.1960C>T, and c.2308G>A) alone or along with mutations in other genes, such as Filamin C (FLNC) (c.2234A>G), Lysosomal Associated Membrane Protein-2 (LAMP2; c.1988G>A) or MYH7 (c.1293C>T), revealed that compound mutations exhibited reduced contractile force (Fmax) with HF compared to single mutations in MYBPC3. The gene discussed is FLNC; the disease is hydrops fetalis.