If a virus enters cells because wild-type envelope motifs interact with insulin, insulin receptor substrate [79, 80], TSH or related molecules [83], or acetylcholine [76] receptors, many variant envelope polypeptides, generated by envelope ORF quasispecies RNAs, would have similar receptor binding affinity, but may effectively disrupt receptor function, predictably causing impaired glucose tolerance or diabetes mellitus, thyroid dysfunction, or myasthenia gravis with secondary resistance to, and elevation of, the normal hormone ligand (insulin, TSH etc.). This evidence concerns the gene INS and myasthenia gravis.