Phospholipid composition of Down's syndrome and normal platelets.

1. Total and individual phospholipids were quantitated in platelets isolated from normal and Down's syndrome (D.S.) subjects. Phospholipids were extracted from isolated platelets, separated by thin layer chromatography and quantitated by measurement of fluorescence of the compounds using a thin layer chromatogram scanner. The total amount of phospholipid was similar in D.S. and control subjects. The amount and percent composition of phosphatidyl serine, phosphatidyl ethanolamine, phosphatidgl inositol, phosphatidyl choline and sphingomyelin was also similar in D.S. and normal platelets. 2. The studies were undertaken to determine if the decrease in Na+/K+ AtPase activity observed in D.S. platelets was associated with alteration in phospholipid composition. The present report would indicate that no major differences in phospholipid composition are present in D.S. platelets that would account for the observed decrease in Na+/K+ AtPase activity.