Human phosphoglycerate kinase and inactivation of the X chromosome.

The fibroblasts derived from the skin of a woman heterozygous for an X-linked deficiency of phosphoglycerate kinase represented a mosaic. Two of 22 clones with normal glucose-6-phosphate dehydrogenase activity and hypoxanthine(guanine) phosphoribosyltransferase activity had no phosphoglycerate kinase activity detected by electrophoresis. Because the loci for glucose-6-phosphate dehydrogeniase and hypoxanthine(guanine)phosphoribosyltransferase are already known to undergo inactivation and to be on the short arm of the X chromosome and the locus for phosphoglycerate kinase is on the long arm, these observations support the conclusion that the entire human X chromosome can be involved in X inactivation.