Glycogen storage disease VII, PFK deficiency is an inherited metabolic disorder affecting English Springer Spaniels. Glycogen is the primary source of energy for the body. Affected English Springer Spaniels have insufficient activity of the phosphofructokinase Enzyme which breaks down glycogen for energy. Deficiency of this enzyme results primarily in easily damaged red blood cells (hemolysis) and less severe damage to skeletal muscle cells. Affected dogs can have pale gums from decreased numbers of red blood cells (Anemia) and may be lethargic or unwilling to exercise. After strenuous activity or periods of excitement or stress, affected dogs may have symptoms of hemolysis and muscle cell damage, which can include red or brown urine, muscle cramping and jaundice. Affected dogs generally have a normal life expectancy, but may have recurrent episodes of hemolysis after exercise and muscle wasting progressing to an inability to walk.