Biochemical Genetics of Neurologic Disease

To the Editor: The review by Dr. Rosenberg in the November 12 issue¹ documents the impressive contribution of biochemical genetics to the understanding of neurologic disease. His discussion of genetic linkage may lead the reader to confuse linkage and association. The statement that “Myasthenia gravis may also be linked to HLA-B8” is not quite correct for several reasons. Certainly it is the genetic susceptibility to myasthenia gravis that was intended here, since the disease has a major environmental component, in view of its low familial frequency, its episodic manifestations, and its autoimmune features. More important, “linkage” refers to loci situated.