Erythrocyte glycosphingolipids of four siblings with the rare blood group p phenotype and their parents.

Erythrocytes that exhibit the rare blood group p phenotype lack the P antigen (globotetraosylceramide) and the Pk antigen (globotriaosylceramide). This phenotype is inherited as an autosomal recessive condition and the red cells of heterozygous individuals, parents and children of p persons, are serologically normal but no chemical analyses of their red cells have been reported. We have studied an unusual family in which all five children exhibit the p phenotype. In addition to the abnormalities described previously, the erythrocytes of four siblings had twice the normal concentration of lactotriaoslyceramide and lactoeotetraosylceramide. These cells also contained 3-5 times as much sialosyllactoneotetraosylceramide and up to a two-fold increase in Gm3 ganglioside. The glycolipids of the parents'erythrocytes were normal. Electrophoretic analysis of the glycoproteins of the proposita's erythrocytes revealed no abnormalities, but her erythrocyte membranes contained approximately 35% less galactosamine than normal red cells. This abnormality resulted from a marked decrease in galactosamine that was soluble in chloroformmethanol. The lipid-extracted residue, which contained the glycoproteins, had a normal galactosamine content.