Most studies find that the amount of phospholamban is not altered in HF (MacLennan & Kranias, 2003) but, because of the decrease in the amounts of SERCA2a, there is a relative increase in the ratio of phospholamban to SERCA2a and this would cause increased inhibition of the SR Ca2+ ATPase, reducing SR Ca2+ content and prolonging the declining phase of the Ca2+ transient. The gene discussed is PLN; the disease is hydrops fetalis.