It is proposed that examination of known X-linked gene products might elucidate the gene loci and genetic defects underlying X-linked muscular dystrophies. On the basis of this hypothesis, kinetic studies were performed on the enzyme phosphoglycerate kinase (E.C. 2.7.2.3.) in blood taken from subjects with Duchenne and Becker muscular dystrophy and from controls. Although no differences were detected between enzyme from any source, it is considered that further study of X-linked gene products is warranted.
