Complex sentence: Both of these diseases result in problems in mucopolysaccharide metabolism however a heterokaryon of nuclei from both of these diseases exhibits normal mucopolysaccharide metabolism proving that the two syndromes affect different proteins and so can correct each other in the heterokaryon.
Split into simpler sentences: Both of these diseases result in problems in mucopolysaccharide metabolism. However, a heterokaryon of nuclei from both of these diseases exhibits normal mucopolysaccharide metabolism, proving that the two syndromes affect different proteins and so can correct each other in the heterokaryon.