Pedigree of the Ohio, Pennsylvania, and Indiana families. The diagnosis of myopathy in subjects O.I.1, O.II.3, P.II.2, and I.II.1 indicated above is solely based on the clinical description of the examining clinicians, in patients with evidence of weakness and muscle wasting that did not meet established criteria for motor neuron disease. No neurophysiologic or pathological data are available for these subjects.